Bizarre Alien Biology

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You don't get more Alien-looking than this.

"Ow, my squeedilyspooch!"

— Zim, Invader Zim, "Dark Harvest"

Extra-terrestrials are weird. Sometimes, really weird. They may look relatively normal or mind-bendingly freakish, but whatever their appearance, you can bet that they don't work like us. They may have green blood or six sexes or any of a variety of other features that make it clear: these are aliens!

Hard Science Fiction is more likely to feature really bizarre examples of Bizarre Alien Biology, though the soft end can get pretty weird at times too, especially when the Rule of Cool or Rule of Funny is in play.

May turn up during an Alien Autopsy. Compare Anatomy Tropes. Assuming that extra-terrestrial life exists (at least in forms more complex than bacteria), this is almost certainly Truth in Television; the idea that life evolving on an entirely different planet would be particularly similar to life that evolved on Earth is so unlikely as to not even be worth considering. If the brain in particular is different, it often results in Bizarre Alien Psychology. Based on a similar concept to the Furry Reminder.

If it is humans who get stuff humans do not normally have, it's Bizarre Human Biology. See also Speculative Biology.

Categories of aliens that may display Bizarre Alien Biology:

Note: Ordered from most human-like to least

Some specific types of Bizarre Alien Biology:

Examples that don't fit in the above categories:

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Anime and Manga

Attack on Titan: The Titans; the fact that how they work makes very little sense is an important plot point, as one of the Survey Corps' stated objectives is to better understand Titans and how to better defend against them/kill them.
From Dragon Ball, we have several different types of aliens:
- The Saiyans are Human Aliens who are insanely aggressive and love to fight, have tails, and can transform into giant apes in the light of the full moon if they still have their tails. Not to mention if they are put close to death and recover, they increase in strength exponentially. Despite this, they can interbreed with humans.
- Piccolo's race, the Namekians, are apparently modeled after slugs. They have visible musculature, the ability to regrow pretty much anything so long as their head is intact (Piccolo once regenerated from being broken into pieces as a statue), and green skin (the muscles are pink, though). They also reproduce asexually and are universally male. There's also an element of Plant Aliens to the Nameks, since the only thing they consume is water and they "eat" via photosynthesis.
- Then there's Frieza's race. They can survive the vacuum of space, can shapeshift to limit their power so as not to destroy their surroundings, and survive without any kind of sustenance for at least a year. (Note that the immense power Frieza and his father wield has been stated to be unique to them: most of their species is not anywhere near as powerful as those two.)
- Tien's race is another one. They can split and create extra bodies, grow extra arms, the ability to look in multiple directions at the same time. Supplemental material reveals that Tien is a descendant of three-eyed aliens who interbred with humans, though originally he was meant to be simply a mutant.
- Majin Buu is not only immune to cyanide, but actually likes the taste of it.
Akira Toriyama must love this: in his earlier manga Doctor Slump, King Nikochan and the rest of his unnamed species have ears on the underside of their feet and butts on top of their heads, crowned with small antennae that serves as their nose, so they have to avoid farting.
A Galaxy Next Door: Shiori Goshiki outwardly looks human, but she has a stinger towards the bottom of her back which sends whoever inadvertently touches it into an infinite void. They are then to become her husband in accordance with her people's customs.
Sgt. Frog: Keronians like humidity, but too much makes them... drunk?
The Emaan of Super Dimension Century Orguss are a species of Human Aliens where both genders have two prehensile tails coming out of their heads and females are rendered biologically sterile by the age of 18-19, compelling them to breed as quickly as possible.
Subverted in Xabungle. Subverted, a little. The Innocent are incapable of surviving on Zora outside of the domed habitats, and so create a few races to do so. Which means that, by the usual logic, it's the Civilians who have this.

Comic Books

In the Harley Quinn series, the titular Villain Protagonist takes a job at the Daily Planet under the alias of "Holly Chance" and publishes a romantic advice column as Chance@Love. One of her readers writes to her asking about the possibility of dating an alien chick. "She can't get pregnant, right? We're different species." Harley writes back, gently chiding him for not seeing some of the potential problems with this:
1. There's just no such thing as safe sex with some species. (Think mate-then-kill.)
2. Who's to say she's the one who'd get pregnant?
3. Two words: Andromeda Strain.
JSA Classified: After being victimized by the organ thieves in "Skin Trade" Loose Cannon managed to stumble to STAR Labs for medical attention without his heart before collapsing.
Played for Laughs in Sergio Aragones' "A MAD Look at Star Wars." Luke Skywalker enters the public restroom in the Mos Eisley Cantina, and does a confused Aside Glance when he sees at least a half-dozen commodes of greatly varying shapes, sizes, and drain configurations.
Oink! comic featured a regular alien called Burp, who was something of a weird gestalt being, in that his internal organs were themselves intelligent life-forms that were capable of leaving his body at any time. Burp would take a long time to suffer any ill-effects from their absence, and once went several months with his liver serving a ten-year sentence in Sing-Sing before he decided to free it.
Starfire (2015): Many of the Strata aliens have bizarre biologies that get Played for Laughs, such as Choor, an alien that only lives for 2 days and becomes pregnant just by Starfire rubbing his head and gives birth to a bunch of tiny furballs.
Superman:
- The Plague of the Antibiotic Man: The Klynn of the planet Tiburon are weird beasts with dog-like orange-furred bodies, clawed hands, elephant trunk and ears, and lizard tails. Their life-cycle is even weirder, consisting of two phases: the living phase and the non-living phase, wherein their bodies shrink and their life processes halt, but they can still talk and move around.
- Superboy (New 52): In addition to the Kryptonian side of his DNA, Superboy states that his "brain" is, in fact, every single atom of his body.
- Superboy and the Ravers: Shaar Q is from an alien race with a lot of tentacles and what appear to be octopi-like siphons on their strangely shaped head-bodies and a long much larger tentacle than the rest serving to to slither along on.
- In the Supergirl story arc Bizarrogirl, the Ash'ka'phageous is a moon-sized, chrysalis-looking, planet-eating lifeform. In order to feed, it spawns swarms of vaguely insect-like, giant, eyeless monsters which land on the targeted planet, eat everything and then return to the primary organism to be processed. A quick x-ray scan by Supergirl reveals they don't even have brain.
  Supergirl: A quick scan with X-Ray vision reveals this thing doesn't even have a brain. It's operating on instinct only. An eating machine.
- Elliot S! Maggin came up with the "Photonucleic effect" to explain Kryptonian solar energy absorption — essentially, kryptonian cells are fusion reactors that require solar radiation as a catalyst to create the necessary chemical reactions.
Superlópez: The aliens from the story Los ladrones de ozono (Ozone thieves) steal the ozone from our atmosphere because it's a drug for them.
In White Sand, the native species of Taldain's Dayside have carapaces of some sandlike substance, making them very allergic to water — it literally melts their skin and teeth — and their innards are blue.
In Wild's End the aliens are either robotic, street lamp-looking beings or wispy energy things. We have yet to find out one way or the other.
Wonder Woman Volume 1: Rykornians are a pyramid headed rhombus bodied One-Gender Race with leaf like hands and feet that is born fully grown from husks on corn-like stalks and can subsequently control the leaves of their birth stalk as Combat Tentacles.
The Green Lantern Green Lantern Mythos prominently features a lot of aliens, so inevitably, more than a few of them fit the bill. Listing them all down would take all day, but here’s some examples:
- There’s Dkrtzy RRR. It is a sentient mathematical equation representing willpower itself. Don’t ask us how that works.
- There’s Mogo the sentient planet, who is himself populated by various strange lifeforms.
- There’s Ch’p and his successor B’dg, whose entire race look like cartoon squirrels.
- There’s Medphyll and Mother Mercy, who are essentially sentient plants.
- There’s Bzzd, who looks like a mutant fly.
- There’s Diamelon, Chaselon and Chriselon, who all look like giant crystal balls with tentacles.
- There’s B’ox, who is, well…Basically a sentient box.
- There’s Rot Lop Fan, who looks like some kind of quadrupedal…shark? Dolphin? What makes him alien is that has no eyes. This makes him different from the other Green Lanterns, because he can’t understand the concepts of “light” or “color”, so he makes his constructs out of sound instead. He also calls the Green Lantern “The F-Sharp Bell”.
In Dr. Blink: Superhero Shrink, the Planet Eater Ginormous mentions that, after eating a planet, he spews the remains back into space as asteroid belts.
Dr. Blink: Binging and purging, gotcha. Classic disorders.

Comic Strips

Mentioned for laughs in Wally Wood's Sally Forth; as Sally prepares to put on a shirt, the Martian Snorky wonders how she can see if she covers her eyes.

Fan Works

In A Better Word Than Humanity, a Rise of the Teenage Mutant Ninja Turtles fanfiction, there is repeated mention that the Turtles's biology is...odd, to say the least. The most commonly brought up bit of mutant turtle biology is the fact they have a fully functional "third ear" of sorts in their snouts where their nasal passages ought to be, giving them super-sensitive hearing at the cost of being weak to especially loud noises and being easier to suffocate/at more risk during respiratory disease.
In the Godzilla fanfiction Abraxas (Hrodvitnon), Monster X (a Two Beings, One Body Artificial Hybrid Kaiju consisting of San and Vivienne Graham) has this. On top of inheriting Ghidorah's bio-electricity, Healing Factor and Alien Blood; their body also possesses two hearts, a third lung (which acts as an "oxygen bladder" when the main two lungs are too damaged to work), a "pre-stomach" organ which is thought to filter out food toxins, numerous glands of indeterminate function. And traces of aurum (gold) in their defective first form's skin and bones, which turns into argentum (silver) after their second transformation. Their second form has both leathery skin, and bone protrusions which act as exoskeletal armor.
A Hero Forged: I.S.A.A.C. manages to surmise that Witches only have one lung to make room for the bile-sack that lets them cast magic. To get around intaking less oxygen than humans, their muscle density is much lower too, so Luz is still physically stronger than most witches even with her nerd-body. Exceptions to the rule — like the super-strong Warden Wrath — aren't technically "witches".
While the movie doesn't go into the details of Megamind's alien biology, the author of Aftermath has lots of fun speculating; Megamind's blue-tinted skin is because his blood is cobalt-based, and after sustaining severe injuries he tends to fall into a "healing coma" while his Healing Factor kicks in. It's a lucky thing too, because MM is also violently allergic to most know Earth painkillers.
Ages of Shadow: Jade ends up with this, as she transforms herself into Yade Khan, giving herself extra arms, hair tendrils, and body pouches, and loses her genitals. And then more changes seem to happen on their own, as while she's recovering from her final sealing, she idly notes that at some point she grew two extra hearts, and her brain moved out of her head. She also mentions that her body temperature is fairly patchwork in nature.
In Arcadia or Bust, during his time at the precinct after being arrested, Jim's half-troll biology is given more elaboration. He has no discernible fingerprints, and his urine sample was so bizarre that the medical professional thinks that he was either pranking them or was in need of immediate medical attention
Nurse: He needs to go to the hospital, ASAP. His sample shows an extreme level of RBC and WBC count, all sorts of weird bacteria and crystals...the crystal count is amazing. Your kidneys must just be stones at this point. …but his pH is… his urine is basically battery acid. It ate through the cup!
Jim: I'm not exactly... normal, anatomically speaking. I'm probably fine.
Nurse: This pH balance is not normal, Mr. Lake! If it was a little lower, I might feel a little better, but it still would mean your kidneys weren't working… I have no idea what this means!
Becoming a True Invader:
- Fefians are blob creatures whose blood has different properties depending on what part of the body it comes from, and possess a Healing Factor which can undo any damage short of being digested.
- Darvons are reptillian beings whose hands aren't visibly attached to their bodies by any sort of limb, but are still fully functional.
The Bridge: Grand King Ghidorah might look like a three headed version of a dragon found on Equestria or ancient Terra, albeit much larger, but it's only skin deep. None of his three heads have a brain, he doesn't need to eat, sleep, or drink and can survive in a vacuum, his "blood" is a molten, golden hued ichor, and the only thing he has resembling an internal organ is a crystalline core in his chest that acts like a heart and brain while housing the souls of all those he's ever killed.
A Crown of Stars: The Empire of Avalon spans several alternate realities. Most of its inhabitants are not baseline humans. When Shinji and Asuka arrive on Avalon they are constantly gaping, since they find all kind of aliens: winged humans, dragon people, shape-shifters, people with multiple arms, insectoids, people whose body seems being covered with ink-black or blue plates... even the more human-like species have enhanced senses or physical capabilities.
A Monster's Nature:
- An examination of Brandon affirms that some elements of his DNA defy categorisation by Earth science, although scientists speculate he might be able to breed with humans.
- After Brandon spends around three weeks being constantly gassed into unconsciousness and nearly starves to death, he quickly regains most of his lost weight by gorging himself on raw meat and other protein-rich foods.
Venom in The Chocolate Shortage needs chocolate the way a normal person needs fresh fruits. After a contamination leaves the west coast almost out of chocolate for a month, Eddie's left pale and clammy with bloodshot eyes and constant sweating. Eventually it gets to the point he tries locking himself in his apartment to keep himself from eating everyone around him.
Daughter of the Titan Even by Boiling Isles standards of odd biologies, Luz's new form due to her half-Titan nature is weird,. During the fight with Hunter she learns that she's immune to the Boiling Sea despite lacking any obvious adaptations for it like most demons with said ability, for example. When Viney gives her a proper examination after her wings and tail come in during an overnight growth spurt, the witch notes that another growth spurt or two is likely, her heart is doing double-duty as a bile sack, with reinforced veins to handle the constant magic flow, and she is literally the healthiest person that Viney has ever seen (meaning that she no longer has lactose intolerance to boot, much to her delight)
The Chronicles of Karai Getting Her Shit Together: While much of Karai's human appearance is left in-tact from the waist-up, she has various quirks that highlight her new snake-mutant body. She very quickly grows accustomed to getting around without legs, she prefers sleeping in dark cramped spaces (like under beds instead of on them), she can get around in the winter and autumn chill perfectly fine despite being cold-blooded (just like the turtles) and while she can eat human food perfectly fine, she much prefers hunting live-animals and she only needs to feed once a week.
Demons like Sunny/Naruto in Dancing with Demons have a digestive system that ends with their stomach where nutrients are simply absorbed directly into their body and they completely lack an excretory system. Anything they can't digest (basically anything that isn't meat) is simply vomited back up later. Furthermore, demons don't actually sleep; instead they go into "Rest" for six hours every week where they're technically conscious but nearly catatonic the entire time. Sunny finds it very unusual that humans need to sleep every night but can be awake and alert instantly, whereas demons need decades before they can throw off "Rest". Next, demons don't seem to breathe except to speak, allowing them to stay completely still for long periods of time. Lastly, any demon can consume the brain of a human to learn everything they know; they have to consume the entire brain to do so but that's because they don't know where memories are stored so eat everything to make sure.
In Enter the Dragon Harry Potter as a dragon has bones made of orichalcum, a stomach made of ceramic and hot enough to boil lead, and can (and does) eat nearly everything, with a particular liking for steel and petrol. Furthermore, rather than grow continuously like most species, he grows rapidly for a couple months every few years then stays the same size until his next growth spurt.
Fractured Sunlight: All of the Rainbooms are biologically not quite human any more, as evidenced in their bloodwork—Twilight says at one point that a pint of their blood could power a truck. Sunset is different even from them, with a horse blood type and a few other oddities that help confirm her story about being a transformed pony.
Kaiju Revolution: The various kaiju have extremely bizarre physiologies that give them their abilities, such as Anguirus having three brains located throughout his head, body and tail or the kaijuform pterosaurs Rodan and Radon how have lungs that can be described as biological jet engines which forces air from openings in their bodies so they can fly at supersonic speeds or use in to fire a high pressure air blast as a Breath Weapon. The creatures of Skull Island are closer to animals that we're familiar with but only by comparison as many of them incorporate plants or minerals into their bodies, among other things. Then there are the inhabitants of Mu that are strange even by this series standards, for one thing, they are all adapted to live in perfect symbiosis with the living island and most of them are entirely female that reproduce parthogenically.
Last Child of Krypton: When Shinji flies into Gaghiel's mouth he gets shocked because it had no real innards, only a tongue and a core embedded in overlapping petals of flesh. He called the body of the alien monster "a mockery of biology".
Lupine Tree has Muzen, a faceless, shape-shifting, deer-like creature with prehensile antlers and a semi-fluid biology. He's almost, but not quite, a downplayed version of a Slime Girl-Blob Monster cross.
The Memoirs of a Reality Jumper:
- The doctors mention not being able to find Alex's left or right starswirls when he's in the hospital. Given how serious they took his joke about being able to play the piano without them, they seem to be related to forelimbs.
- Likewise, Alex finds Pony beer to be too salty for him. Applejack initially thinks he's a lightweight, until he explains that humans need roughly one tenth the amount of salt daily that ponies put in a single glass of beer or cider.
In Neither a Bird nor a Plane, it's Deku!, Dark Shadow is a fifth-dimensional genie whose body (which looks like a living shadow) feels simultaneously bony and spongy.
Not Human (Or Anything Remotely Close), a The Owl House fanfic, takes what the series occasionally implies about witches and goes full ball with it. The inhabitants of the Boiling Isles grow fangs in their teenage years, somewhat akin to Baboons, to intimidate their enemies and thus rarely display their teeth when smiling, have a second stomach for purifying demonic impurities in their food (that a human, if encountering, ends up having to expel flames from their mouth to remove instead), can have gems imbedded into their bodies when their magic bile sac is matured, are unfamiliar with calluses (though this is implied to be from a lack of hands on work than a full undevelopment of them), can outright purr to show affection, have sharper hearing from their pointed ears that in turn are very sensitive to touch, and can casually lose limbs to easily re-attach or regrow with magic (the later taking a lot longer and using more energy).
Re: My Hostage, Not Yours: The Valkians are Bee People, whose bodies also generate a magma-like substance from their rocky skin.
In Rogue Knight, H'ara'k demons use ground up gems as medicine, line their nests with gold (which their young absorb through their cocoons), and require platinum to breed. One such demon, Samantha "Sammy" Gardener, works as a fence to make it easier for her to acquire said materials for her clan.
An interesting variation is mentioned in Tame that when she was applying to become a police officer, Judy Hopps had to take the polygraph test three times before the officials gave up as the test was designed for large animals and couldn't work with Judy's much higher heart rate.
Thousand Shinji: All three of the Children evolve over time in ways that are truly bizarre. From Rei being a Poisonous Person and Plague Master whose blood could wipe out all life and whose tears cause fungus to grow rapidly where they fall, to Asuka who has a body temperature of over 110 degrees Fahrenheit, has titanium bones (which she had to drink paint to get the nutrients for), and can change into a red skinned berserker with hair made of bronze. Then Shinji who has roughly triple the nerves of a normal human along with multiple pseudo-brains that free up the actual brain in his skull to be fully devoted towards his psychic powers. Their evolutions also apply to their Evangelions; while Asuka's grows stronger, faster, and tougher, Rei's loses most of it's armor and all it's fluids are extremely corrosive, causing Ritsuko to theorize any attack on it would over-penetrate and see the attacker doused in acid.
Raven is completely unaffected by alcohol in What Happens in Vegas due to her demonic heritage, but a date rape drug acts like ecstasy.
The Unexpected Rookie: The Autobots, at first glance, look exactly like the inhabitants of the Cars world...except of course for the fact that they can transform. After Mirage is heavily damaged in battle, Ratchet uses Doc's clinic to patch him up. Doc watches some of the repairs, and is clearly fascinated by Cybertronian mechanics.
In Xenophilia, several ponies note that human sweat smells like cologne to them, with Big Mac stating it's rather unfair that Lero sweats a scent he has to pay good money for.
Zim the Warlord: Irken Reversion: Irkens are already this in canon, but it gets expanded on here, such as the fact that they can taste through their palms. But the Reverted state that Zim ends up in shows that they used to be even more bizarre — he ends up with an extra pair of arms, his legs are triple-jointed and strong enough to let him jump a full story in the air, his circulatory system can absorb oxygen straight from the air through his skin, and he has an extendable dart under his tongue which drains blood and stores it in one of the new organs that formed out of his squeedlyspooch (later revealed to be for the sake of powering a Healing Factor).

Film — Animation

Home (2015): The Boov have six legs each, change colors when experiencing different emotions, discharge gas from appendages that grow out of their head (which also seem to be their noses), have flexible skulls, can eat almost anything, and apparently have a third form of waste disposal. And they have two uvulas.
Monsters vs. Aliens: The four-eyed alien conqueror Gallaxhar drinks tea through his ears.
Phineas and Ferb The Movie: Candace Against the Universe:
- The aliens on Feebla-Oot breathe and exhale oxygen, making carbon dioxide a rare commodity for them. They also explode into goo from the waist up when excited, which sounds exactly like someone shouting the name "Candace", but regenerate from it in less than a day.
- The Cowards have things on their backs that expand into shells making them hide like turtles.

Film — Live-Action

Alien vs. Predator:
- The Xenomorphs' longtime foes, the Yautja, from the Predator series, have their own weird biology. Most notably, the "dreadlocks" they wear don't appear to be hair at all. Prop skulls from Predators show large sockets for the tendrils. Expanded Universe material suggests that the dreadlocks are in fact hair, melted together into tendrils in an incredibly painful rite of passage. Of course the Yautja are still bizarre, what with their glowing yellow-green blood and eyes that register heat rather than visible light. Depending on which source, instead of melted together, braided together. The process takes days and is very painful. If the subject so much as winces in pain, the whole thing is undone and must be done again from the beginning.
- The Xenomorphs themselves have battery acid as a bodily fluid (which reacts to the metals extracted from their food to generate electricity), iron teeth and claws, and a carapace of "polarized silicon" which means they have glass for skin. They also extract DNA from their hosts when gestating.
In Avatar, most animals on Pandora breathe through spiracles in their chests rather than nostrils and possess six limbs or appendages.
In Infini, the bio-agent responsible for the death of a mining crew, one search and rescue team, and almost a second, is so bizarre that the scientists sent to that planet first thought it was a sort of ore that could be used for fuel. When it thawed, it demonstrated the ability to mimic tissues and organs down to the cellular level.
Invasion of the Saucer Men: The Saucer Men have sharp fingers that can inject alcohol into people, causing them to die from alcohol poisoning. If they are killed, their hands can detach and run amok on their own.
In Mars Attacks!, the Martians only speak in their own language but can still understand human language, bleed green, their heads explode upon hearing country music, and, according to the novelization, they vomit by shedding tears.
In Men in Black, half the humor and plot points are drawn from the biological characteristics of the aliens they encounter, and K's encyclopedic knowledge thereof. No matter how weird they look, almost all of them find ways to pass for a human. Or, in one case, a small dog. Or, in one novelized case, potted trees. Of course, the MIB refuse access to Earth to anything that cannot blend in with humanity. The second movie had a subway-train-sized alien worm with a tiny flower on its head hiding just beneath the surface, disguised as a weed.
MonsterVerse: Generally, the Titans and the creatures of Skull Island, though terrestrial, have such bizarre biology that it almost justifies the Acceptable Breaks from Reality (such as the winged Titans taking flight in Earth's atmosphere and their ability to move their sheer mass fluidly in Earth's gravity). For examples; the MUTOs are stated to be mammalian despite their insectoid, reptilian and dinosaur characteristics in their appearance and reproductive cycle, Kraken/Na Kika has multiple hearts and brains and can fake cell death, and many of the species inhabiting Skull Island are Planimals.
- Lampshaded in Godzilla: King of the Monsters (2019), when the Monarch scientists note that Ghidorah regrowing a severed head in seconds and No-Selling the Oxygen Destroyer's suffocating effects "violates everything we know about the natural order"; right before The Reveal that the Alien part in his Bizarre Biology is literal in his case. Ghidorah also bleeds black blood in an earlier scene. And although promo materials indicate each of Ghidorah's heads has a brain like a terrestrial organism, Mike Dougherty states most of his neurons are scattered throughout his entire body and limbs like an octopus, which enables his heads to recover their memories and personalities if they're lost and then regenerate.
Nope: Jean Jacket's insides resemble billowing nylon cloth, and it can somehow bunch itself up into a compact saucer shape with only one "mouth" opening, even though its true form is a jellyfish-like organism. Somehow, it is able to both generate an EMP field that shuts down electronics and generate a perfectly stationary cloud around itself for camouflage- both common elements of UFO sightings.
Phantasm: Whatever he is, Tall Man's biology is baffling; he bleeds yellow, has a Sentinel instead of a brain, and any severed body parts become weird insectoid monsters.
Save Yourselves!: The pouffes are a species of aliens that resemble animate pom-poms, with features such as eyes or mouths not being visible. They also feed specifically on ethanol, consuming Su and Jack's sourdough starter and whiskey, as well as draining their car's gasoline.
Thirst (2015): The alien monster in this movie has a proboscis located in its chest. It can shoot the proboscis out at will and use it to suck the vital fluids out of victims.

Literature

The War of the Worlds (1898) is probably the Trope Codifier. Martian biology is very bizarre but still grounded in realism. The Martian is a cephalopodan creature consisting of an oversized brain and a mass of long tentacles: Wells suggests that humans might evolve into something similar as technology advances to a point where all organs atrophy into redundance, and all that is left is the brain and a manipulator. They have two large disc-shaped eyes, and a weak chinless mouth that feeds directly into a basic heart and lung system, and they have no digestive system of any kind; the body is sustained by intravenously injecting blood from other species. Perhaps most importantly, technology has rendered all Martian disease long extinct and so the Martians have no immune system, and this eventually proves their downfall.
Animorphs is fond of this trope:
- Hork-Bajir are covered with blades, which have the innocuous purpose of helping them trim edible bark from trees. They have two hearts and a Healing Factor so good that one casually cuts open his head and shows off his brain to prove that he doesn't have a Yeerk.
- That's nothing compared to the Skrit Na, two species in one. A Skrit is basically a giant, fairly stupid cockroach, which at some point spins itself a cocoon and apparently dies. However, out of its dead body comes a Na, a smarter (but still weird) creature which is basically a member of The Greys.
- Leerans are froglike aliens with Psychic Powers; their weirdest feature, though, is that you can rip off half of their brain without any apparent problem, which is useful for removing Yeerks.
- The Yeerks themselves, of course. They look like gray slugs and can take over the brains of other species. Instead of eating, they absorb their home sun's energy while swimming around in swamp-like Yeerk pools, and need to do so every three days to survive. They apparently have No Biological Sex, but reproduce when three Yeerks merge together, then disintegrate into hundreds of baby "grubs."
- Andalites are blue centaur-like aliens with no mouths who eat through their hooves, have an additional pair of eyes on prehensile stalks, and speak through telepathy.
Chanur Novels:
- The kif have two sets of jaws, one at the front of their mouths and one at the back. The front set of jaws is used to rip flesh off of still-living prey, while the second set chews the meat into a paste before swallowing it (the throat of a kif is so narrow that it's incapable of swallowing anything solid). Further, the kif are carnivores who can only eat fresh meat, where "fresh" means "could be used in organ/muscle transplant operations". Meat that most other species of carnivores would consider fresh will make kif so nauseous that even when starving to death they'll be unable to eat it.
- The t'ca (giant methane-breathing snake-worms) give birth if subjected to enough psychological stress. They also have five brains and their language has a matrix-grammar rather than a linear one.
Comes up in, of all places, The Chronicles of Narnia, when it is mentioned that centaurs have the stomach of a man and the stomach of a horse, and both appetites are very large, so a centaur's breakfast begins at sunrise and lasts until mid-to-late morning. (If looking for a specific reference, this is close to the end of The Silver Chair, after escaping the underground realm).
Cluster has numerous biologically bizarre aliens, including a water-squirting ball that lives off atmospheric gasses, magnetically-levitating disks of metallic particles that communicate by laser, a teardrop-shaped being with a single tentacle who rolls on a track-ball instead of legs (said ball also serving as the egg for females) and tastes the ground as it rolls, and sentient slime-fish with three sexes.
In the Cthulhu Mythos, Mi-go look like crustaceans with batlike wings and a fleshy orb covered with small tentacles in place of a head, but biologically they are closer to fungi (and they're not really fungi either. It's just what they resemble the most from Earth organisms). The Elder Things are described as being something akin to a mix of vegetable and crinoid. This is not to even mention the Great Old Ones, which are not really made out of matter in the strictest sense of the word.
The Cheela from Dragon's Egg are a pretty extreme example: living on a neutron star, they're not even made of atoms, but rather of tightly packed atomic nuclei. Their body "chemistry" being based on nuclear reactions, millions of times faster than normal chemical reactions, they live and think much faster than humans, which is central to the plot. The fact they're also half-Plant Aliens and Blob Monsters that can create and dissolve their bones at will is just the icing on the cake.
In Dreamsnake, the titular creatures superficially resemble ordinary small snakes, and are most notable for the use of their venom as a narcotic and painkiller. Unfortunately, they're rare and difficult to breed in captivity. The protagonist discovers that this is because they actually need biological input from three parents — to mention exposure to extreme cold — in order to successfully reproduce.
The Xsarn of the Gamester Wars trilogy resemble tentacled insects who form a seasonal hundred-person "mating ball" to reproduce and eat feces. Since other species' wastes contain little food energy, they must eat almost constantly, and so Xsarn tend to carry feeding troughs with them everywhere. Making it worse, they tend to regurgitate when they get overexcited (which happens a lot). And You Do NOT Want To Know what their greeting ritual is like...
The Souls from The Host (2008) leaving aside the fact that they have no eyes (or mouths?), have blood and other tissue that's silvery in color, and are effectively a very squishy, gracefully flowing centipede with brain-controlling tentacles, their reproductive method, which involves suiciding queens splitting apart into thousands upon thousands of tiny little babies is... well, yeah.
From Larry Niven's Known Space series:
- The Pierson's Puppeteers have three legs ending in hooves, two heads that "resemble Cecil the Seasick Sea Serpent puppets" and double as hands, and have their brains in the middle of their torso.
- Bandersnatchi are giant slug-like single-celled organisms with a single chromosome as thick as your finger. Also quite possibly the oldest surviving species in known space.
- The Gw'oth come from an icy moon not unlike Europa. They are five-limbed octopuses that can link with each other to become incredibly intelligent supercomputers.
- The Pak, from Protector, as well as the later Ringworld books, are a subversion. On the face of it, they're suitably weird aliens. They begin life as little better than animals with no ambitions beyond eating and breeding but, when they reach forty-two or so, they eat a special root (or rather the virus within it) and transform into a truly bizarre protector form with swollen joints, toothless gums fused with the lips, massive changes to the brain, a second heart in the groin, and skin thickened into leathery armor. A protector's sole purpose is to keep its descendants safe, no matter the collateral damage. If its bloodline goes extinct, it just stops eating and dies. As it turns out, however, they're actually a case of Bizarre Human Biology — humans and Ringworld hominids both descend from lost Pak colonists, known to modern science as Homo habilis, and modern aging is a result of our bodies trying to undergo the protector change with the virus' additional genetic material. If the virus is eaten, however, any Pak-descended organism can still become a protector.
- The Outsiders, who dwell in the cold vacuum of deep-space and have a liquid helium based biology. They are described as looking like a cat o'nine tails with a fattened handle (the "head"). They "eat" by placing their head in sunlight and their tails in shadow, which sets up a temperature gradient which generates thermoelectricity. They move around in zero gravity by jetting tiny puffs of gas from their tails. They are very secretive about their reproduction, but it might have something to do with the Starseeds they follow around the galaxy.
- From the Man-Kzin Wars Shared Universe anthologies (and since then included in a story by Niven himself), the Jotoki: five-limbed multi-jointed amphibians who are actually composite organisms consisting of five semi-sapient limbs fused together and neurologically linked at the center. Individual limbs may be different sexes, and one limb typically stays awake to watch out for predators while the others sleep. Jotoki can be very indecisive when their brains are in disagreement. Jotoki temporarily split to mate, and their young are non-sentient tadpoles that grow into "sea snakes" which finally fuse in groups of 5 to make an adult Jotok.
Monk: In one of the books, a convention for a Star Trek parody is in town. The protagonist is an alien with pointed ears, a trunk, and three mouths.
The One Who Eats Monsters: Among Ryn's various biological differences, she has six gill-like slits on her back, from which she can produce black, razor sharp fibres she calls her "kanaf", which she can control to use as armour, clothes, a weapon, camouflage, grappling hook, ect. She can even change its colour and texture, which she uses to make it appear that she is wearing human clothes. It's a little bit like an angel's wings, and a little bit like an eldritch abomination's tentacles. The clothing made from her kanaf can be removed from her body, and worn by somebody else. However, it remains a part of her. Naomi describes it as oddly warm, and Ryn is rather embarrassed by being wrapped tightly around her entire torso.
Retief: One of the recurring themes is bizarre alien biology that doesn't fit the preconceived notions of the Obstructive Bureaucrats in the diplomatic corps, leading to horrible snafus that only Retief can sort out. Some of the weirdest are the Lumbagans, where what we'd think of as an "individual" is actually a colony of many autonomous organ-creatures (spleens, eyes, duodenums...) working together.
The Demonocles in Rumo & His Miraculous Adventures have incredibly complex tongues containing a structure akin to a secondary spinal cord. Break it, and you have crippled the Demonocle (and scared the living shit out of his buddies).
The Sector General series lives by this trope. It's a hospital that caters to the most outlandish cases in the galaxy, treating aliens of all shapes and sizes. Really' all shapes and sizes; Rubber-Forehead Aliens is completely averted in favour of whatever the author mind could conceive. The effects budget is not an issue in novels.
From the mainstream Star Trek Novel Verse:
- Far from being the deadly poison it is for humans, arsenic is a required part of a Klingon diet and Klingons who go an extended period without consuming arsenic can develop health problems.
- Syrath are crystalline life-forms who can regenerate themselves from only small pieces due to non-centralized anatomy, making them effectively immortal, if subject to personality change depending on how much original material is retained.
- Frunalians undergo a metamorphosis during their adult life in which their exoskeleton falls off, their biochemistry (and personality) change and a fleshy mane-like sensory organ erupts down their backs. Frunalians know this change as "the Shift".
- Pacifican Selkies also undergo a metamorphosis, from amphibious breeder to fully aquatic adult; again, part way through their adult lives.
- Seleneans are able to link their brains together through specialized spines that permit them to alter each others' brain chemistry as a means of communication.
- Several of the species featured in Star Trek: Ex Machina, whose physiologies and cultures are expanded from background material associated with Star Trek: The Motion Picture. These include the baleen-feeder Megarites, who require "drysuits" when out of water, and survive on nutrient injections where they can't filter-feed. Then there's the Zaranites, who rely on fluorine-dependent micro-organisms as part of their respiration.
In the "Shatnerverse" series of Star Trek novels, where Kirk is resurrected after his death in Generations and goes on to live in the 24th century, the main characters encounter a super-secret group of Starfleet black-ops scientists with some pretty wongo ships. Several crew members are fully holographic, for example. The captain of the lead ship, a woman named Raddison, has a holodeck for a ready-room, and she appears in a different form with her room set to a different natural disaster recreation to different characters; a small Chinese woman to Kirk, a striking blonde to Riker, etc. In the end, Kirk asks her to at least tell him, among all of her secrets, which of her forms is the real one. She smiles and says, although using a plot reference instead of these words, that he's short-sighted for assuming all species are bipedal. Kirk, at this point, realizes that no matter what her holodeck ready-room looks like, there is always one single constant in the room that never changes. Captain Raddison is the room's potted plant.
Star Wars Legends often describes the unusual biology of aliens. In the films, the details of a species are rarely gone into in any depth.
- The Codru-Ji starts life a dog-like creature with 6 legs the size of a Doberman. As adults, they look like normal humans, only with 4 arms. No fur or otherwise canine features remain.
- Banthas. Seriously◊.
- Black Fleet Crisis: Yevetha have their brains in their thoraxes, which are also protected by thick bone. They also have auditory cells on their temples. On their wrists they have retractable dewclaws that could shoot out and surprise opponents unaware of them, extending a foot in length. They can also tolerate much greater g-forces than Humans.
The entire landscape in The Stormlight Archive is like this. Probably has something to do with the massive highstorms coming every couple days. Most of the plants and animals look like things you'd find underwater, with the ability to retreat into hard stone in the case of danger. Extra bonus goes to the Parshendi, who are humanoid but literally grow their own armour (as in, it's a part of them), which weirds out people in-story. Shinovar is the only exception, having a number of plants and animals that we would find more familiar (chickens, in particular, have been exported to the rest of the continent). Wit, a centuries-old world-hopper, repeatedly expresses annoyance at what he finds to be a thoroughly depressing landscape.
Wit: Perhaps a story for a child. I will tell you one, to get you in the mood. A bunny rabbit and a chick went frolicking in the grass together on a sunny day.
Kaladin: A chick...baby chicken? And a what?
Wit: Ah, forgot myself for a moment. Sorry. Let me make it more appropriate for you. A piece of wet slime and a disgusting crab thing with seventeen legs slunk across the rocks together on an insufferably rainy day. Is that better?
Kaladin: I suppose.
Year Zero features a smorgasbord of weird aliens.
Clifford Simak was prolific at creating imaginative aliens, often at least three or four new ones in each novel or story. Just in Project Pope, there were Dusters (sentient clouds of dust) and Spheres (spherical aliens that had to make themselves beat like a drum to talk to humans) among quite a few others.
Plenty of this in the Riesel Tales: Two Hunters anthology.
- One creature shown in Club Gig is like a glassy woven vase that speaks in chime and bell noises.
- Btabo shapeshifters can convincingly mimic other species (including their clothing) and shift their features to change direction without the need for turning.
- Qinmoirs are eighteen-foot-tall bear/crab people who breathe air with much higher oxygen levels than standard beings can handle, and can see in standard and ultraviolet wavelengths.
- Fruburwhas are four-armed mudpuppy/spider beings who can regenerate lost limbs, breathe above and below water (their gills look like feathery ears on their heads), and see only in ultraviolet wavelengths with their pearly, pupilless eyes.
Speaker for the Dead: How bizarre the aliens are becomes a plot twist, as it reveals why the "piggies" murder two humans. It happens because in order to have babies, pequenino males have to turn into a tree. The piggies were trying to honor the men by making them into fathers — and only after the men, not understanding the process, had refused to similarly kill them.
In Ukiah Oregon, the Ontongard/Pack reproduce by taking over and duplicating other life forms. They store short term memory in their blood and long-term memory in their DNA, and every cell is a pluripotent stem cell that can turn into any other kind of cell at the drop of a hat. Severed pieces can turn into any animal of the right mass that the creature has touched before and flee or keep fighting.
Aside from sentient plants, interdimensional beings and such, one of the novels by Janusz Zajdel features sentient anthills. They are functionally immortal, as long as they get light of certain wavelenghts — without it, they lose the eusociality (somehow). Oh, and they really love honey and certain inedible (to humans) mushrooms.
A lot of Eden Green is spent exploring the biology and various species of alien needle creature invading a Southern city.
Every living thing from Hender's Island in Fragment, despite the fact the organisms are all of Earthly origin. The island is veritable Death World in miniature, and everything eats everything. Many organisms are able to breed from birth (or even in the womb), and go through numerous life stages, and are able to reproduce during each stage to produce offspring of that stage. It's also implied that everything on the island is technically immortal, because everything gets killed so quickly that a natural lifespan is pointless. One specific example would be the Hender's ant, which doesn't even vaguely resemble an ant despite its name. It has a circular body and moves by rolling on its side, controlling its speed and direction by extending and retracting appendages from its rim, or simply flipping on its side and walking normally. It can also launch itself at a target and spear prey with its spiny appendages like a shuriken. Every ant carries its offspring on its back, which carry their own offspring, which carry their own offspring and so on until they reach the size of dust mites. If the parent is killed, the offspring pour out to consume them and anything else organic they encounter, essentially making them biological grey goo. The ant can also turn into various types of Hender's "plants" by rooting itself to the ground or become microscopic symbiotes of larger animals.
The Starchild Trilogy: At the reefs of space, between the stars, life has evolved from primitive cells called fusorians, which actually fuse hydrogen and other elements to produce energy. They have evolved into a wide variety of odd creatures—most notably, the friendly spacelings and the terrifying living rockets known as pyropods (flame-foot).
Robert J. Sawyer is known for making his aliens truly alien. Tosoks in Illegal Alien have a different bodily structure from most Earth beings, with radial symmetry, for instance — they have one arm at the back too. Plus, their females have four uteruses and are usually impregnated by an equal number of males in turn. It's thus common to have half siblings. Calculating God also has two different alien species which have entirely dissimilar bodies from ours.
Whatever species the protagonist in Quicksand House are (Human-Terramyte hybrids, if you're curious), adolescent females of it grow antlers and claws and have violent psychotic fits where they attack everything in sight. This is all perfectly normal and nothing to worry about. So sayeth Nanny.
Villains by Necessity: Centaurs are blue-green colorblind in the book's universe, along with (logically) having two hearts and two sets of lungs.
Isaac Asimov:
- "Homo Sol": When the story begins, Tan Porus is investigating the unusual biology of a squid from Beta Draconis IV. He's discovered that a highly specific sequence of lights and sounds puts the squid into a coma, with no clear reason why this would happen.
  "If you shift the wavelength of any of the light units by fifty angstroms either way — any one of them — it doesn't sleep. Shift the length of duration of a light unit two seconds either way — it doesn't sleep. Shift the pitch of the tone at the end an eighth of an octave either way — it doesn't sleep. But get the right combination, and it goes straight into a coma."
- "The Imaginary": The squid from Beta Draconis IV, when exposed to the light-spectrum of mercury, emits a glowing field of death that could expand to interstellar distances.
Worm:
- It is eventually revealed that at least two of the three Endbringers possess bizarre internal structures. The Endbringers are composed of multiple crystal layers, none of which have anything resembling cells, which get progressively denser until they violate the rules of how atoms work. At the very center of this is a core of simple organs.
- Then there's the Entities, which are giant multidimensional worms that reproduce by seeding other lifeforms with power-granting bits of themselves.
The Goosebumps book Earth Geeks Must Go features aliens that eat through their armpits.
The whole plot of Robert Sheckley's "Hands Off" is about an alien and a human pirate crew finding themselves on each other's ship. The humans are almost killed by the basic life support systems, like a blade designed to peel off dead skin layers and an industrial strength nutcracker, while the alien complains the human ship doesn't have the most basic systems - at least, until he finds a few bottles that can serve as a skin care lotion. When the humans at last manage to get the ship off the ground, it turns out they cannot turn off the life support, which is set for temperatures well above what humans can survive. They barely manage to land, run for their ship while the alien takes his back... and then discover that the "skin care lotion"^notesafe cracking acid by human terms made huge holes in the hull, and the alien already lifted off with their toolbox onboard.
The Sackers from The Three Minute Universe are different from the usual Rubber-Forehead Aliens commonly seen in Star Trek. Their skin is transparent, with sickly colored organs visible from the outside and little white bits flitting back and forth that are described as looking like maggots feeding on a corpse. Combined with their intense smell, just being around one causes most other races to get violently sick. Their voices are incredibly loud and high pitched to the point that a few words can cause temporary deafness. They thrive in environments too hot for others to live in and their skin is so hot that a casual brush can cause second degree burns. As a result of this, they are dreaded throughout the galaxy, despite being a peaceful and respectful race.
The Kaiju Preservation Society: Everything in the alternate Earth, starting with the fact they view uranium as a tasty, tasty snack. The kaiju aren't so much animals as mobile ecosystems — mature kaiju have their own organic nuclear reactors, complete with a set of parasites specifically evolved to act as air conditioning so they don't overheat.
All three major alien species in The Night's Dawn Trilogy, plus Bitek is ubiquitous outside Earth so many humans are so boosted that they fall into Bizarre Human Biology. However, special mention must go to the Kiint. The Kiint are the most advanced known species in the galaxy and look like a bit like giant polar bears with six limbs that function interchangeably as arms or legs and can change shape. When a young human girl visits the Kiint's homeworld, which isn't even inside the Milky Way Galaxy, it turns out that there are multiple subspecies of Kiint, including avians and marine mammals, who look nothing alike and yet are somehow still sufficiently genetically related to interbreed, to the point that the Kiint seem to view them as ethnic groups rather than different species. The girl's Kiint friend introduces her to her cousin, who looks like a plesiosaur. She asks how they can be related when they look like completely different species, and her friend basically replies "some humans have dark skin, what's your point?"
Remembrance of Earth's Past:
- Trisolarans only appear in one scene in The Three-Body Problem and are never given a complete description, but we know a handful of details: they can mummify themselves at will to enter a state of suspended animation, they communicate through flashes of light (and have no real barrier between thinking something and saying it), and reproduce by fusing together and then splitting into several new Trisolarans, which inherit some memories from their parents.
- In The Redemption of Time, Yun Tianming becomes the first and only human to lay eyes on a Trisolaran. Their most salient feature is that they're no larger than rice grains, which has had profound effects on their intelligence and psychology. The irony of them calling humanity "bugs" is the first thing Yun realizes.
The Doublers in Eden qualify, as might be expected from Stanisław Lem. Their name derives from their bodies appearing to consist of two parts: a big, bear-like translucent section which is similar to a shell or coat, but which is also used for walking, and a small, thin brownish torso with arms and a head which is connected to the inside of the shell and can be retracted into it. The translucent shell is revealed to have once been an electric organ used for defense, and they are able (thought they prefer not to) directly extract nutrients from the soil.

Live-Action TV

ALF: Melmacians have ten major organs, eight of which are stomachs, they get denser instead of fatter, and they have green blood.
Alien Nation: The basis for 1/4 of the show's humor. Newcomers can't get near saltwater, it's like taking a bath in battery acid for them. They blink when they sneeze. Partway through a pregnancy, the female transfers the natal pod to the male. Instead of getting headaches, their feet swell when under stress. Their bodies cannot process cooked meat proteins (they can eat it, but they don't get anything out of it), so they eat their food raw. They also have a nerve cluster under their arms that produces the same effect as a Groin Attack on a human.
Angel:
- In the episode where Fred has her body usurped by an Eldritch Abomination, she and Wesley spend the first couple of minutes fighting some small gremlin-like monsters, then discussing the creatures' biology. She describes a portion of their reproductive process, which evidently involves crystals, bacteria, and parasitism.
- Lorne mentions that his heart is located in his rear. He can also survive decapitation, and once had his unconscious mind physically removed (result: it became a hulking Enemy Without, while he became unable to sleep and his psychic powers got gradually messed up). The comics reveal that doing something contrary to his character- murder- can give him cancer.
Babylon 5:
- The station is home to a number of aliens with different biological needs. Probably the best example is the Centauri; the males have six tentacle-like... members to go with the female's six... "slits", two hearts (one of which is also the kidney), and have no major blood vessels in their wrists. Since they appear to be human aliens (with funny hairdos), this is somewhat notable; the Centauri themselves reference this a lot.
- Aside from the obvious physical differences, the Minbari also differ from humans in a number of less obvious ways. For example, Minbari do not perspire the same way humans do, nor do females menstruate in the same way human women do (apparently, as after becoming half-human, Delenn didn't know what the "odd cramps" she began experiencing were). Externally the reproductive organs are similar to those of humans but internally are quite different. Minbari also cannot consume even the smallest amount of alcohol as it causes them to become violently psychotic.
- The station itself was designed to accommodate a diverse range of species. Different sections of the station could be rotated at different speeds for those aliens needing higher or lower gravity and parts of the station are equipped to provide those aliens who don't breathe oxygen with suitable atmospheres.
Doctor Who:
- While the Time Lords look perfectly identical to humans on the outside, they have two hearts and possess several strange powers, including the ability to regenerate when they are about to die, causing them to immediately reset their cells and biological makeup and reborn with a new body and slightly altered personality.
  - However, in the TV movie it is pointed out how problematic this biology is, as when some human surgeons try to operate on the Doctor his biology causes them to accidentally "kill" him, forcing a regeneration.
  - Time Lords also have the ability to ward off many different kinds of poisoning. As seen in "Smith and Jones" they can rid themselves of radiation poisoning by channeling the radiation into their clothing (his shoe, in the Doctor's case), and "The Unicorn and the Wasp" has the Doctor cure himself of cyanide poisoning by having ginger beer, walnuts and anchovies, then getting snogged by Donna. It's a bit less specific than that as he asked for ginger beer, something protein-rich, something salty and a shock.
  - They also have a "respiratory bypass system", which means strangling them doesn't work. Drowning still does, however.
  - Depending on who wrote the episode Time Lords are actually a rank, not a distinct race, and at least some of these traits are something they gain when they attain it. Baseline Gallifreyans have very long lives in human terms but don't regenerate, and the Doctor supposedly only had one heart before his first regeneration.
  - It's been indicated that they might have multiple brains: In "The Bells of Saint John", the Eleventh Doctor says that he has 27 brains before backtracking as a "slight exaggeration"; Missy indicates she has multiple brainstems in both "The Magician's Apprentice" and "Extremis"; and the Thirteenth Doctor's comment about asking her brains, plural, to work in "Praxeus" does not go unnoticed by her companions.
  - "The Tsuranga Conundrum" mentions something called an "ecto-spleen".
- The Dulcians in "The Dominators" had two hearts before the Doctor suddenly always had them. In the case of the Dulcians it's to make them fit the "bleeding-heart liberal" stereotype ("Two hearts and no curiosity" was the description in the script), though this doesn't entirely come off due to the writers bungling their own analogy.
- The Alzarians from "Full Circle" outwardly resemble humans, but are the descendants of a group of Marshmen who colonized a spacecraft from the planet Terradon after it crashed on Alzarius. As such, they retain some of the Marshmen's highly adaptable physiology, which includes being able to recover from illness or injury more rapidly than humans. Indeed, Adric (a young Alzarian who joins the Doctor on his travels) is quick to point this out when Tegan says he needs to rest after spraining his ankle:
  "Don't worry, Tegan. We Alzarians are different from you. We recover faster."
- "Planet of the Ood" hangs a lampshade regarding the titular species, who among other things have a secondary "hind" brain they hold in their hands, connected via a Hive Mind to the gigantic Ood brain. The Doctor tries to examine a dying Ood, but he isn't familiar with their biology and has no idea where the heart is, or even if they've got one.
Farscape is, unusually for a TV series, full of truly bizarre aliens (as well as having the usual complement of humanoid and Rubber-Forehead Aliens).
- Hynerians fart helium when nervous or angry. Their bodily fluids also become flammable/explosive after ingesting a certain root which is then used as a catalyst for Peacekeeper beam weapons.
- Luxans can survive in a vacuum for a time, and their blood is clear when healthy and cloudy when ill or injured. If this happens they need someone to hit them very hard until the blood turns clear again. And there's their tongues, which are longer than the rest of their body, and contains a spectrum sedative capable of knocking out almost any living creature it touches.
- Then there's the fact that Scarrans don't have external sexual organs, which Chiana discovers after collapsing in agony from trying to knee one in the mivonks. They also have an internal body temperature high enough to melt some metals and can fire heat beams from their hands.
- Pilot, and other members of the species known as "pilots", are adapted to be able to physically link with and communicate with the intelligent starships, to the point where removing them is dangerous. They also have strong regenerative capabilities, including the ability to regenerate a limb.
- The intelligent starships themselves, like Moya, are adapted to work with the pilot species, and, in general, to have human-like creatures living inside themselves. The degree to which the DRDs (repair 'bots) inside Moya are biological and part of her, vs. being mechanical and independent, is somewhat unclear as well.
- Sebaceans look exactly like humans, but can't regulate their body temperature, when overheated they suffer from "heat delirium" including short-term memory loss and culminating in an irreversible coma, they also have a single "paraphoral nerve" instead of kidneys, and when pregnant can hold an embryo in stasis for up to seven years.
- Delvians (being a race of Plant People) enjoy certain types of light very, very much. They also have a skeleton that's made of wood rather than bone.
- It'd probably be quicker to give a list of aliens on that show who don't qualify.
Logan's Run:
- In "The Collectors", one of the alien races captured by the Kasorlans cannot survive in Earth's atmosphere for more than two minutes as it is toxic to them. The atmosphere in their cell is equally toxic to humans.
- In "Stargate", Timon says that the aliens were extremely tall and thin prior to assuming human form. They retain their extreme vulnerability to cold.
The Magicians (2016): Fairies turn out to gestate from eggs that grow off mushrooms.
Marvin from Nick's Fantastic Comedy Marvin Marvin has five stomachs, though one is apparently used to emit a mating call. The gases in Marvin's stomach also allow him to float when he's really happy.
- Marvin apparently has the ability to superheat or supercool his finger.
- When Marvin gets a toothache in the third episode (aptly titled "Toothache") the tooth has to be removed before it explodes.
The Orville: Moclans are an all-male species... who lay eggs to reproduce... and are sometimes born "female".
The Outer Limits (1995):
- In "The Grell", the titular race have a biological process known as Grell alchemy which is capable of altering the DNA of other organisms. Jesha uses his saliva to neutralize the radiation found in fruits which grow in the vicinity of Old Seattle so that they are safe to eat. If humans are exposed to Grell blood, it has the capacity to alter their DNA so that they become Grells themselves. After Jesha heals his master High Secretary Paul Kohler at the insistence of his wife Olivia, Kohler begins to turn into a Grell and gains some of their characteristics such as the ability to see ultraviolet light by day and heat signatures by night.
- In "Think Like a Dinosaur", the air that the Hanen breathe contains three times as much carbon dioxide as the air on Earth.
- In "Rule of Law", the Narkopta have a two-hour daily hibernation period.
Red Dwarf. The Cat's internal organs are color-coordinated, and his heartbeat and pulse are so cool the Captain tells the ship's doctor to put it down on a tape for him.
Star Trek has a few examples beyond its usual Human Alien and Rubber-Forehead Alien groups.
- Like the Trill, who are (two or) three species with separate degrees of this. The Trill symbionts are alien slugs that live for millennia, and can bond with humans or humanoid aliens. Though only the humanoids of their own homeworld are suitable as permanent hosts. Semi-permanent, rather, since once the host dies the symbiont gets transplanted into a new one. Given that this is done surgically, how did the humanoid Trill and symbiont Trill ever even figure out that such a thing was possible? It's not as if when two sentient species meet, surgically implanting one into the other is a logical thing to attempt. Obligate mutualism is a thing, but this is still something of a stretch.
- A Starfleet officer on Star Trek: Deep Space Nine named Vilix'pran (whose species has not been shown on screen) "budded" many children. Who had wings that had to be kept from tangling. Oh right, Vilix'pran takes the pronoun "he".
- Deep Space Nine also had the Changelings, a race of shapeshifters whose default form is gelatinous liquid and who live in a collective living ocean called the Great Link.
- One Deep Space Nine episode has a Breen being exempted from blood tests to see if they're a changeling, because they have no blood to test. The Changelings, who are mostly very uncomfortable around solids, appear remarkably at ease around the Breen...
- The freaking Ocampa. Lifespan of nine years. Body temperature around 16 degrees Celsius. Can only have one child. When ready to mate, they exude a yellow substance from their hands and must have an hour-long foot massage within 50 hours of the substance appearing to enable mating. Give birth standing up, from a sack between their shoulders. While their psychic powers probably helped, one still wonders how a species with such bizarre, not to mention mathematically troublesome, method of reproduction could have come about in the first place.
- Vulcans: In the original series, Spock often exhibits this, most famously with his green blood and pon farr, much to Dr. McCoy's amusement and occasional surprise. Being raised on a planet that has a significantly warmer climate than Earth, Vulcans are used to warmer temperatures and become increasingly sensitive to cold as they get older. Arguably, this is lampshaded at the end of "Operation: Annihilate!", when it is revealed that Vulcans have an inner eyelid, like cats:
  McCoy: Unusual eye arrangement. I might've known he'd turn up with something like that.
- Klingons have redundant organs that will engage if they suffer enough damage to their primary organs.
- Not to mention the Horta in the original series episode "The Devil in the Dark" — silicon-based lifeforms whose eggs look like metallic nodules, which is the Plot Point of the episode.
- The pilot episode of Enterprise had a brief appearance by the Lorillians, a species that needs to be weaned from one atmospheric gas to another at age four. We are never given any explanation for how this worked.
While only shown in a single episode, Procardians in Time Trax appear human but tend to glow brightly (which they can voluntarily suppress to appear human). They are also able to levitate for a brief time. When threatened, they instinctively blast the threat with an energy pulse that is powerful enough to put a human in a coma. Their vocal cords are unable to produce human sounds, although they can learn to understand human speech. Their own speech sounds extremely strange and creepy to humans (think modulated inhuman wailing). The oddest thing about them is how they age. Instead of gradually changing like us, they stay the same for years until approaching a threshold, at which point they quickly (and painfully) change into an older form, which may make it difficult to recognize the same person. They are a peaceful race, who consider humans to be far too primitive to initiate First Contact. They finally change their minds in the 22nd century, although a scout ship of theirs visited Earth in the late 20th century.
The Twilight Zone (1959):
- In "Mr. Dingle, the Strong", the Martian scientist has two heads while the Venusians have antennae.
- In "Will the Real Martian Please Stand Up?", the Martians have three arms while the Venusians have three eyes.
- In "Hocus-Pocus and Frisby", the aliens have a Venusian specimen who can sing at eight different pitches simultaneously and accompanies himself with his tail.

Mythology and Religion

Classical Mythology:
- The excreta of the bonnacon, a bovine creature of Greek myth, catches fire upon contact with air; the beasts use that particular quirk in their anatomy as a weapon.
- And there's of course the hydra with its quite impressive regenerative physiology in regard the decapitations... And that's just the tip of the iceberg.
Japanese Mythology: According to the Kappa myth, they have three anuses, enabling to pass three times as much gas as a human.

Pinball

The Martians in Revenge from Mars are shown to drink gasoline like it's alcohol.
Many of the creatures in Crüe Ball fall under this trope. One example would be the Cerebral Cyclops, which look like a brain with one eye and a short tail.

Podcasts

Comes up often in Mission to Zyxx for all the "weird bug creatures and stuff" referenced in the intro. Examples include Dar (who drinks sand and is 50% empty space), Sammo and Wink (Wink is a bud growing out of Sammo's back), and Bory (her lower half is pie).

Tabletop Games

Pathfinder: Dwiergeths are bulbous creatures with two mouth-tipped tentacles instead of a head and legs ending in five-lobed feet lined with suckers, see the world through photosensitive hairs instead of eyes and, instead of regular digestive systems, have pocket dimensions made up of a seemingly endless maze of tooth-lined intestines.
In Rocket Age some species have striking similarities to humans, others... do not. Ganymedians are Plant People, while Europans have six genders and no skeleton. They use cartilage based structures and a second circulatory system to somehow move around like a regular humanoid.
Warhammer 40,000:
- The Orks are hybrid animal/fungal beings whose tissues have as much in common with a mushroom's as with a human's. Upon their death they release spores that in turn give birth to Orks and other creatures linked to them (snotlings and squigs, for instance) — they're essentially invasive ecosystems, each member of which can seed spores that will give rise to all other species. They also never stop growing. If they get wounded and are allowed to heal, they grow even faster. Normally living organisms have a genetic limit on how big they can be, or they are limited by the environment where they live, but orks and their sub-species can grow infinitely.
- The extremely fascinating but sadly now out-of-print book Xenology takes place from the standpoint of an Imperial scholar who over the course of the book studies the physiology of all the major alien races of the setting, as well as a few of the lesser known ones. Needless to say, this trope comes up a lot — even the humanoid aliens possess organs capable of releasing mind-control pheromones or blood that crystallizes instead of clotting.
Low-Life: Aliens come in all kinds of shapes and powers. The one constant feature of an alien is that NO ALIEN has an anus. All aliens have such an incredibly good digestive system, that no being from another planet needs to take a dump. It's this, that allows someone to find out if they're dealing with aliens or the local mutant population.

Toys

BIONICLE doesn't get into it often, but it's still there.
- One example that sticks out is when the Skakdi race, in part of their description as repulsive and gross, are mentioned to chew and swallow their food like animals as opposed to simply absorbing energy like everyone else does.
- The franchise's LEGO roots are given a nod in rare instances when the characters' ability to rebuild themselves is mentioned. Under special circumstances, they can reattach separated limbs, instantly regrow decayed muscle and repair themselves with specific pieces, though the latter requires special knowledge. Some can also fuse with each other, during which their parts and spirits meld with each other as long as they concentrate, while the Makuta race can forcibly absorb others to gain their mass and destroy their spirits.
- The Makuta are individual parts of a sentient Hive Mind liquid called antidermis, made into biomechanical cyborgs whose life process involves their musclemass, organs and minds turning into gas at a certain age, after which they gain the ability to leave their bodies and possess machines and lose all biological needs.
- Certain animals in the lore come equipped with tank treads and suspension gear in place of legs, which is never ever commented on as something unusual.
Tamagotchi: Tamagotchis come in all weird shapes and forms, from round balls, to being a talking wine glass, to being a washiki toilet with a giant poo and then an actual sentient giant wad of poo. However, they all eat, communicate, marry and produce offspring with no trouble at all.

Video Games

In Coffee Talk, Neil's biology is never really explained in detail but we do get the key detail that they drink through their finger. This also applies to their sibling Amanda.
While most of the aliens in DEADLOCK are pretty standard Space Opera, the Uva Mosk (think a three-way cross between a shrub, a human, and either an anteater or a turnip) definitely fall into this category.
Dead Space: The Necromorphs are Hive Mind obeying alien bacteria that reanimate corpses into various Body Horror Demonic Spiders. Destroying the head doesn't slow them down, and unloading ammo into their torso doesn't either. Only hacking off their limbs, tentacles and yellow tumor-like growths stops them from turning you into food or another corpse to reanimate. They can even convert dead body parts. Say you have a chopped-off finger that gets infected by the necrovirus: It'll sprout tentacles and spines and attack you. They're basically The Thing (1982) IN SPACE. Though less paranoia about who is one, and more paranoia about when one is gonna pop out of air vent and tear you a few superfluous holes.
In Destroy All Humans!, from Crypto's point of view, cows are disgusting. They're covered in nipples and eat with their mouths!
Crypto: Ugh, I think I'm going to be violently ill!
The monsters of Evolve. They have no cerebral cortexes, they can manipulate the world in ways humans need machines to do, they consume massive amounts of meat before burning it all to go through years of growth in seconds, and despite the wide variety in monster strains they're all so similar on a genetic level that one might mistake them for samples taken from a single organism. That's not getting into their origin: they're all physical bodies created by an extradimensional race of energy beings. The bodies are constructed with what they know of the material universe, which means they are capable of growing guns and engines as easily as muscle and bone if they know how it goes together.
Most creatures in the Grow games works in strange ways, because the games use toon physics and the creator puts emphasis on creativity. In general, the way a creature works depends of the game, and pretty much every creature can transform in strange ways by interacting with an object or being in a specific place, but there are examples that are consistently weird.
- The Onkies have no faces, but can see and eat just fine, and their heads may also fall from their bodies, but their bodies can simply pick them up and put them back again. When they get exhausted, they melt as if they were made of wax. They also come in different colors that indicate either their gender, age or expertise depending of the game. Sometimes, they have the ability to self-duplicate.
- The Tonties are cyclops with horns. They live underground in colonies like ants, their colors and number of horns indicate their roles, and their queen is a big white Tontie-head with no body. One way for a white Tontie to become a queen is to have a crown fall on it. Its body is crushed under the weight of the crown and its own head (which also somehow gets bigger as the body is squished). Also, a different creature may turn into a white Tontie simply by falling into a spike. A big eye then appears on the creature whose original face somehow disappear and the spike become the newly-created Tontie's horn.
- The Rotta/Pierre is a creature that changes completely depending if it's daytime or nighttime. Its "Rotta" form, which it takes during the day, is a blob monster that can shape-shift. Its "Pierre" form, which it takes during the night, is a round bat-like creature that splits in two if it's tapped by a hammer after which a Onky comes out of it. Gluing the halves back brings back the Pierre to life but changes its colors.
In Lusternia, humans are regarded this way. The ability to specialize into different skills? The capacity to interbreed with other races? Freaks! (It helps that in Lusternian lore, humans are from a different dimension entirely.)
Mass Effect:
- Quarians are examples of Mirror Chemistry, mentioned above. They also evolved on a world where, apparently due to the strange nature of local microbes, their immune system evolved to adapt to and assimilate foreign microbes instead of rejecting them as with all other species in the galaxy. This made them extremely vulnerable to infection from more hostile microbes, though it's explained the problem is less the microbe's doing and more the efforts of the quarian immune system to assimilate it. Three centuries in sterile spaceship environments has only made their immune systems even weaker, forcing them to live permanently inside sterile suits.
- Turians in the same series are avians with similar Mirror Chemistry to Quarians, requiring them to eat their own specific sorts of food or risk digestive distress. They also have the unique trait of metallic scales covering most of their body, as a survival response to the weak magnetic field of their planet, which allows for much more solar radiation. All other life on their homeworld has the same type of metallic exoskeleton.
- Krogans are noted for their redundant organs: having multiple sets of organs helps when their main organs are badly injured, although the changeover between systems frequently causes a rush of adrenaline and neurotransmitters that produces a state known by the cheery name of "blood rage". One well-noted example of this redundancy is their four testicles, referred to colloquially as a "quad". They also heal very efficiently, although a straight-up Healing Factor is only possessed by a tiny amount of outliers; one character describes a krogan who visibly regenerates in combat as a freak of nature. Krogan also don't have a traditional nervous system. What they have instead is a second circulatory system filled with an electrically conductive fluid. This makes them nearly impossible to paralyze.
  Shepard: The Normandy was destroyed. I ended up spaced.
  Wrex: Well, you look good. Ah, the benefits of a redundant nervous system.
  Shepard: Yeah, humans don't have that.
  Wrex: Oh. It must have been painful, then.
- Volus are native to world who's life catalyzed in ammonia rather than water. This, combined with the intense atmospheric pressure necessary for such a biosphere, requires them to wear environmental suits in Earth-like atmospheres to prevent themselves from suffocating and exploding.
- The vorcha are a species with no terrestrial analogue, although a loose comparison can be made to worms found around deep-sea vents. Their bodies are filled with non-differentiated cells that can adapt to suit the individual vorcha's needs. Dump a vorcha in an atmosphere with low oxygen content? Those cells move to the lungs to make them more efficient. Dump him on a high-gravity world? Those cells move to the muscles to make them stronger. Set a vorcha on fire but leave him alive? The vorcha gains fire resistant skin. However, because of their twenty-year lifespans, most vorcha can only take advantage of this adaptability once.
- Asari can mate with any sentient species in the galaxy and produce viable offspring. This includes just about every species you see listed. Talk about Boldly Coming. It's indicated that they actually use their partner's DNA to randomise their own, producing a genetically unique child. Asari can also obviously mate with each other, but this is frowned upon in their society as it can lead to producing an Ardat-Yakshi. They also, apparently uniquely, seem to possess genuine Psychic Powers and not just the biotics almost anyone can get - they can perform a mind-meld with a sexual or romantic partner. The children they have with other species also aren't Half Asari Hybrids, but are always just asari. That being said, there are apparently some differences, the known one daughter of an asari and krogan is gleefully coarse and violent, and asari vorcha offspring are apparently consistently allergic to dairy.
- Salarians are a race that evolved from amphibious precursors, and they reproduce in a similar fashion to amphibians; females lay eggs, and males inseminate the eggs afterwards. Fertilized eggs hatch into females, and unfertilized eggs, males. This also gives way to salarian slang of calling someone a "cloaca" (the cloaca being a sac in amphibian bodies that is part of both the excretory and reproductive systems - in other words, an "ass" and a "dick"). Furthermore, the accelerated metabolisms of salarians give way to increased brain function, helping salarians become more intelligent, but at the cost of having significantly shorter lifespans than any other race in the galaxy, with the exception of the Vorcha whose lifspan is even shorter - Mordin Solus, who is approximately 40, is considered practically geriatric by salarian standards.
- Over in Mass Effect: Andromeda, the angara have bio-electricity and will die if they can't get regular sunlight.
In Metroid, Kraid is a relatively normal looking three-eyed dinosaur — except for those awfully large spikes that constantly shoot out of his belly.
Pikmin is no stranger to species that are just downright weird, but the Quaggled Mireclops introduced in the third game takes the cake, the pie, and the last cookie. It's basically a chunk of land with a fruit-like appendage. Attached to this is a pair of vines with eyeballs on the ends. It also walks around on three hoof-tipped legs, with the hooves apparently tied to its nervous system. Underneath the "stalk" of the plant bit is a perfectly round lip from which a massive purple (and strangely human-like) tongue can reach out. If Pikmin are still on top of it when it stands up after being downed, it stands on two legs and tips them off... somehow. This is even more jarring when compared to the rest of the game's enemies, which at least partially resemble actual flora and fauna.
- The Onions themselves are this. They are not the same species as Pikmin^note, despite acting as a nest to them. They make more Pikmin by absorbing nutrients, whether they be from other plants or dead animals, but some of the nutrients are instead used as fuel to fly, with the flower on top stabilizing, and they are capable of surviving in the vacuum of space with no harm. When absorbing animals they are able to copy their traits allowing new Pikmin to gain those traits, but can also do this with other onions, or onions of the same types. With different types of onions they merge into a single Onion, allowing multiple types of Pikmin to be propagated in the same place, but with onions of a type they already contain, it's instead used as nutrients and fuel. The Rock and Ice Onions stockpile Ice and Rocks for their types of Pikmin, the Hermikmin to inhabit when created. They have muscle fibres despite being a plant and are still unable to walk, though the muscle fibres give them a small range of motion, being able to push itself move into a place where they are easily begin flying or landing when stuck.
Rise And Destroy: One piece of loading screen text claims that Frankie Forearms has four hearts.
Shockwave has the Pericata, who have a bone in their reproductive organs that can be easily fashioned into an earpiece for humans that noticeably improves hearing acuity. After the character who makes these is met, the entire crew can be seen wearing them.
Spore has the Grox, a race of Always Chaotic Evil cyborgs who can only survive on planets with a Terrascore of 0 — planets that are otherwise incapable of supporting life. The moment a planet's Terrascore goes up to 1 and becomes the least bit hospitable, every Grox on the planet will immediately die. Abducting Grox using your ship's tractor beam will also result in their immediate death, since your ship's cargo hold has an atmosphere that is hospitable to other species, but toxic to the Grox. It is speculated that this is why they guard the center of the galaxy so fiercely, as it contains the Staff of Life, a device capable of Terraforming any planet to an idyllic Terrascore 3 garden world in a matter of seconds, making it essentially an anti-Grox WMD.
Star Control aliens include anything from Blue-Skinned Space Babes to living crystals crackling with electrical discharges and innate hyperspace communication capability, to Eldritch Abomination Hive Mind chatting in Starfish Language.
StarCraft:
- The Zerg. Their organ tissues randomly mutate (and, in certain cases, steal new DNA from a new prey creature), and their hyperpowered immune system hunts it down, invoking "survival of the fittest, nature red in tooth and claw" on the genetic level. This allows a piece of formerly dead and rotten Zerg tissue cultured in a laboratory to un-decompose, and evolve 1000,000 times more than humans ever have in the space of a week. Their alpha amino acids have unique "R groups" that allow damaged cells to fuse with protein to repair themselves. It also allows them to ignore Biochemical Barriers by adapting to be compatible with host organisms. They can reproduce through parasitic fusion, or larvae produced from a building that eats mineral crystals, drinks liquid vespene gas, and is built around six wombs (complete with birth canals), a brain, and a stomach. Their buildings are really self-contained organisms that are based on the genetically programmed nest site architecture of their prey species, and one building is specifically designed to do that ultra-evolution thing at an accelerated rate. They don't need to breathe, and their flesh is dense enough to count as a spacesuit. Their metabolism is so fast that, on top of meat, they eat minerals and drink vespene (which is a mutagen, so that helps things along considerably). The downside to this is that they are very susceptible to radiation poisoning.
- The Protoss are relatively normal biologically in comparison, but that's not saying much in light of the above. They've got digitigrade legs, and No Mouth, which they make up for by being photosynthetic and able to absorb water vapor through the skin. Also, with a bit of training, they can turn pure rage into wrist blades and cut you to pieces. With a bit more training, it's either invisibility or climate-altering Psychic Storms.
The web-game Trials in Tainted Space is an erotic space opera and thus has a lot of aliens the player can meet and do more if you so desire. While most aliens have standard humanoid parts the Nyrea, humanoid/insectoid aliens take the cake. For starters, the males look like elf females with chitin plates, while the females of the species are One Head Taller with a large ovipositor what looks like a horse dick with spikes at the tip. The female uses her ovipositor to rend the males sperm sacs to fertilize her eggs and if she's the alpha of the group she'll lay get lesser female to carry them in her. Yeah.
The Selenites in Voyage Inspired By Jules Verne are a race of blur-skinned aliens with bulbous heads with glowing growths on their sides, squat torsos, three fingers on their hands, and VERY long arms and legs. They also speak in a variety of flute noises, but are perfectly capable of speaking English.

Webcomics

The Accidental Space Spy explores evolutionary biology using bizarre aliens as examples.
Drive (Dave Kellett) has Skitter, who can detect gravitational waves with his mohawk.
Played for Laughs in Ellie on Planet X, with examples including the bathtub — actually an alien whose mouth is conveniently bathtub-shaped.
Enemy Quest: The Visitors, save the Skut, are all Humanoid Aliens. However, a Visitor would never be mistaken for a human.
- Oculots: They have one eye and they can shoot fireballs from it. They have spines on their hips and shoulders. They have very long tongues and can live up to 800-900 years old.
- Warriors: Big, red, four-armed soldier creatures with fiery, orange eyes. They're ridiculously strong and tough, and as a culture are extremely competitive.
- Skut: Speedy rodent-lizard hybrid critters with six eyes and acid for blood. An individual Skut is actually a single personality and intellect spread over multiple bodies.
- Floaters: Half-cybernetic flying things. Instead of lower legs they have powerful jet boosters. They are all very cold and emotionless. Every Floater is a clone of another Floater.
Exiern:
- Dragons leave their young in the still smouldering embers of burnt out buildings, the baby dragons resemble normal human infants and grow up looking like (and thinking they are) humans until they reach their late teens when some sort of homing instinct draws them towards other dragons. They spend some time in a half-human/half-dragon state while they gradually lose their human identities, before growing into their final dragon form.
- Also, squirrels "reproduce by magical cloning and there is but one all-squirrel connected through a collective psychic consciousness".
In Goblins, Kin the yuan-ti (basically a human with a snake tail instead of legs) mentions that she has two stomachs.
Gunnerkrigg Court has at least two Merostomatozons, one of least bizarre features being that they "have 47 eyes and 15 not-eyes". Also, descendants of a female fire elemental.
Hitmen for Destiny has this down to an art form. These usually come in the form of Professor Lostclock Dripkettle's incredibly descriptive narratives about the various odds and ends of the monsters that inhabit the many worlds of the comic from the stomach monsters who find their prey through living portals that lead to a giant stomach; to the fibra, who may very well be the least efficient creature to ever live.
Homestuck:
- Trolls have a caste system divided between 12 normal blood colors (the "hemospectrum") which goes from short-lived, psychic rust-bloods all the way up to violent and dangerous bluebloods and sea-dweller violet bloods, with the fuchsia-blooded empress and her current heir at the top. They have an insect-like life cycle and are born from a separate mother grub species which takes in genetic material carried by drones in pails. Genes from couples that feel the strongest love or hate for each other tend to win out of the incestuous slurry, and troll gender is irrelevant to reproduction. And that doesn't even go into all the bizarre anatomical details hinted at by "auricular sponge clots", "bone bulge", "chitinous windhole", etc. However, this may just be an artifact of the trolls' language, as a bathtub is called an "ablution trap".
  Trolls sure are weird!
- For all the trolls' weirdness, cherubs outdo them easily. They're hatched with split personalities of opposite genders and character alignments as a default feature. Puberty for them involves a Split-Personality Takeover (not to mention the growth of wings). And then there's how they mate...
- Equally bizarre, perhaps even more so, are the Leprechauns. While we haven't gotten the full details, they seem to be a One-Gender Race with bodies made of green felt, they can vary greatly in size, and their method of romance involves combinations of nine different emotions, represented by charms, only one of which equates to human love or troll matespritship, and most of which involve pranks, riddles or games of chance. Unlike the four "quadrants" of troll romance, any of these relationships could lead to reproduction following a "mating jig", though some combinations of charms yield better chances for reproduction than others.
In Irregular Webcomic!, Iki Piki has a "splanch" (at least he does before his organs are harvested). Its purpose is unexplained, except that without it he'll die. The Darths & Droids version of Zam Wessel has one as well.
Kill Six Billion Demons is filled to the brim with utterly strange life forms. Notable examples include Angels (Energy Beings encased in armored shells who are physically incapable of breaking the Law), INGSVLD (a knight with a floating book for a head), the Kind People (creatures that look like a cross between a spider and a horse), and Etlin Da (a Blue-Skinned Space Babe with a harp growing out of her head). Amusingly, all the other races consider humans to be the ones with a bizarre biology, since we’re the only sentient species that can’t reincarnate.
Love and Tentacles: Not only do the tentaculas have three different types of tentacles with very distinct purposes, they also have a two-pronged tongue.
A Magical Roommate: Daria is a dragon who decides to live with humans on a whim. While she's very interested in tools and technology, she is completely repulsed by the fact that humans eat, of all things, plants! Her later revelation that fairies eat bugs spurs her to try to fix this problem, but she forgets about it almost instantly.
Ozy and Millie: Not really an alien so much as a mythical creature, but Isolde (a dragon) claims that she conducts photosynthesis.
Downplayed in Res Nullius. The alien protagonist has nothing that would surprise the average science fiction reader, but her reaction to her human partner gives off this vibe.
According to Steven, the Instrumen from The Sanity Circus are hollow and do not eat.
There are countless examples of exotic alien species in Schlock Mercenary:
- A standout example is the F'sherl-Ganni, a species of giants who were the preeminent power in the galaxy before all those upstart younger races started causing trouble. Notable features include four arms (each of which split at the elbow into two separate forearms and hands), the ability to survive extended periods of time in hard vacuum, apparent immortality, horns on their head which also serve as long-term writ-large memory storage, and three tongues. That said, they are also an extremely advanced race, and it's difficult to tell how many of these traits are natural elements of their biology and how many are the result of genetic engineering.
- Schlock himself is a Carbosilicate Amorph, who are stated to be evolved from a self-repairing computer memory unit. His biology features the ability to make virtually any chemical compound and gives himself an acid bath if he's smelly. His entire body functions as an ear, a nose, and a broom, and it's made out of ultra-strong carbon fullerenes. However, his eyes are actually fruits from a tree that was likely genegineered to produce visual organs by his ancestors' creators, and he can install or remove as many as he wants at will. At one point, a hazmat team mistakes him for Grey Goo and they technically aren't wrong — it's just that this particular piece of ancient rogue nanotechnology is sophont and has a preferred size that he normally doesn't exceed. He has a distributed brain and thinks with his whole body and if separated those fragments can still be sapient though missing the memories the other fragment contained. It also means that any battle damage he takes is technically brain damage, which may partially explain his personality. He can eat practically anything, including concentrated solvent and foreign nanobots, and has an immune system capable of taking on those nanobots and winning. The nanites have only been Too Spicy for Yog-Sothoth and spat out once. It's implied that on a microscopic level, he isn't even cellular.
The insectoid Cirbozoids of Starslip take this to an intentionally comical extreme. For starters, they reproduce asexually (the exact process is never shown); have alkaline blood they can spray through their vestigial eyes (they see with their antenna); they have dorsal gill slits that become clogged with excess blood and need to be purged periodically to keep their hearts from stopping; their carapaces secrete Ritalin; their vital organs are held in their abdomen, making almost their entire body expendable; and their natural mode of walking is skipping. Once, Memnon praised the natural artistry in some crystalline structures in Jinx's cabin; they were the result of the Cirbozoid equivalent of a head cold. And they can only breathe out. Also Mr. Jinx produces Bourbon as a waste product, much to the delight to the local rehabilitated space pirate.
- On multiple occasions, the ship has been saved by any of a variety of gases or fluids that the Cirbozoid crewmember produces. Once, early on, he asks that they get some security personnel so that they can get along without the constant need for his secretions.
- As one comic demonstrates, Cirbozoids are quite literally a Do Anything Species — if you have a need to be met, a Cirbozoid can probably use some highly specialized reproductive processes and give you a temporary to cover for you until the permanent replacement arrives.
- It's not only their bodies that are different, but their brains; they are incapable of understanding art. This becomes a major plot point.
Trying Human has three alien species (and that's only counting the sentient ones), and the weirdest of these must be The Greys: no discernible sexual organs, no sexual dimorphism, inexplicable size dimorphism, and according to John, they only have one organ in the first place (it looks kind of like a purple intestine). Besides that, their mouths are vestigial — they eat liquid protein (made from abducted cows) through their skin, which also senses taste (Hue's first contact with seawater is a surprise). They communicate solely by telepathy.
Incase's Not Safe for Work webcomic Xenobiology has an Earth-born Puazi woman named Anna Jelenko as the protagonist. Puazi biology has the unfortunate habit of reacting to human biology by making them sexually aroused. While it varies from one Puazi to another, Anna's reaction is very strong.

Web Original

Athyrmagaia has the Athyrmatherians, which, in a strange example of this trope, resemble familiar Earth animals like lions, gazelles and wildebeest: except that the head, thorax, abdomen and rump of each Athyrmatherian is a separate animal of its own, having metamorphosed from four separate sibling larvae that then proceeded to unite at adulthood.
The strangers from Goodbye Strangers. Most of them look like gigantic brightly colored worms with a varying number of eyes and limbs. It is unclear if strangers are even technically living things because most of them do not need to eat and they appear through Spontaneous Generation and most of them cannot reproduce in any way and cutting open a stranger reveals that they have no functioning internal organs. Instead, they are entirely filled with random objects and materials with seemingly no purpose. Some are filled with brain tissue or intestines or body fluids, others are filled with inorganic materials, and some are even stuffed with trash or are entirely hollow. And several strains are completely flat like Paper People, and others are nearly liquid Blob Monsters. Their eyes are not actually real eyes, but are just eye-shaped markings on their skin, and yet somehow these eyespots are what allows them to see. Why strangers even exist at all is unclear but it is hinted that they are embodiments of human emotion.
SCP Foundation, SCP-839 ("Candied Worms"). SCP-839 are worms that are somehow alive despite being made up of sugar, coloring and flavoring.
Chakona Space gives us the Faleshkarti, whose semen contains a hormone that makes their partners stupid. Permanently. Note that the Faleshkarti are hermaphrodites, and also that they have very very high sex drive, particularly at the onset of sexual maturity. As a result, the children do a lot of the important work, including scientific research.
M'Lai: Every time they are inseminated, they get a fresh injection of the hormone. They are literally fucking themselves stupid.
The short film "Danger: Humans" plays with this trope by demonstrating our species' Bizarre Alien Biology from an alien point of view.
Madgie, what did you do?: Toki's species is something called "erin" (pronounced EE-rihn). From what is shown about her species, they are mammals, females can reproduce asexually (something that doesn't occur in mammals), the babies are born with teeth, in-utero development for said babies seems to pretty quick, they have something of a healing factor, and they apparently tend to age rather slowly, along with living for a long time. Apparently, the aforementioned's blood isn't a unique thing, as that also can occur with other members of the species.
Cirno, in Touhou: a Glimmer of an Outside World, has bones made of ice.
DSBT InsaniT: Sand Snake can still eat, despite his head being completely separate from his body...which is made up of a bunch of floating lines.
From an alien perspective, the human protagonist in Humans Don't Make Good Pets seems to defy physics. Despite being less than half their size, he can eat an entire week's worth of rations in a single sitting and drink a full quart worth of water (they usually drink about half a cup worth), while also being an omnivore which is described as insanely rare in the galaxy. That he's also a Pint-Sized Powerhouse who can ignore kicks from something twice his height and break down spaceship doors only compounds things further. That's not even touching on the harmless (to humans) viruses and bacteria in and on his body which are extremely deadly to aliens; alien rats that got infected all died with some committing suicide, others melting, and one spontaneously exploding.
- Vzk'tk, the alien race that took in the human protagonist, have an Adaptive Ability that makes them immune to viruses and bacteria over time. Unfortunately for them, Earth viruses and bacteria mutate far too fast for their bodies to adjust. Even though they're only infected by the weakest and most versatile ones, they're still enough to lay out most of the crew and have them scrambling for a state of the art medical facility.
Orion's Arm: Most aliens in this setting are in no way compatible with earth-like habitats. Though in a subversion, the classic sci-fi example of silicon based life is almost completely unheard of; the only instance that's ever been found were some very slow moving crystals that were about as intelligent as anemones, (until they were provolved, naturally).
- The To'ul'h are vaguely bat-like aliens from a "wet greenhouse" planet (similar to Venus, though cooler and with water). A To'ul'h on earth would die from freezing, alkaline burns, UV radiation, suffocation, and decompression,
- The Muuh look like crabs and come from a planet similar to Titan, meaning it's cold enough for hydrocarbons like methane to be liquids. Their biochemistry is based on liquid hydrocarbons instead of water. A Muuh on Earth would literally melt and/or vaporize.
- The Daharrans are considered "humanoid" solely because they breathe earth-like air (they are crustacean/mammal-like), and they're the some of the only aliens found out of dozens of civilizations that can do so.
- The Magvivistem Hyperpolity is also incredibly strange, though technically created by Terragens. It is home to forms of life made from magmatter^note, which reacts on timescales many times faster than normal chemistry, and yet cannot congregate too closely together without collapsing into a black hole due to their density.
- Any a-lifes and virtuals can have virches with vastly different physics, and so in their worlds, their biologies can be even stranger than the strangest xenos.
The Mystery Flesh Pit has a lot of this going on. Between its physics-defying size, lack of any discernible body plan, exotic bodily fluids, vast internal ecosystem and apparently being the only example of not only its species but its entire phylum, one has to wonder whether it's even native to Earth in the first place.
Starsnatcher: The Seizers have their mouth located between their six pillar-like legs. Also, they apparently lack bones and instead have very stiff muscles.
ᴛʜᴇ ɴᴏᴇᴅᴏʟᴇᴋᴄɪɴ ᴀʀᴄʜɪᴠᴇꜱ: Word of God confirmed that Kirk Odd's species is called the Otherkind, a species of aliens that primarily do not have physical forms. When they do take on physical forms, they do not look like ordinary humans. They either have a Cyclops eye or Extra Eyes, and they either have Extra Digits or are missing digits from their hands.invoked

Western Animation

Roger of American Dad!. He regularly excretes some sort of yellow, slippery substance from his sides. If he doesn't get his bitchiness out, it turns to bile and poisons him. He can also gain all of someone's memories by anally fingering them. He can move at Super-Speed, is fireproof, and can implode a grown man's head with an elbow dive; the latter two abilities he was unaware of. And he has an extremely long lifespan, as of the show he is over 1600 years old and still apparently quite young.
- In one episode Hayley accidentally reaches into his chest and takes out his pancreas (somehow), which snarls at her and runs off. Roger is indignant, saying he'll have to spend the rest of the night setting out traps for it.
- And his poop is solid gold and jewel-encrusted (though, this depends on what he eats).
- Roger is also shown to have an unnervingly long tongue.
- This was at some point lampshaded in terms of sex when Roger (in his "Jenny" persona) had sex with Steve's friend Snot when Steve asks, "You're an alien how is that even possible?!" to which he tried to explain how but was interrupted. Later, Roger reveals to him that he has put a stress ball between his legs and Snot has been having sex with that. An earlier episode ("Decon Stan") suggested his species is hermaphroditic, which adds more questions.
- In a later episode, we see he can turn himself inside out (but can't turn himself outside in).
- If he goes without sex for a year he turns into the Grounch and in this state he attemps to sabotage others from having sex and can only turn back to normal if he does intercourse.
In Atomic Betty, Sparky is a Big Eater, but it's hard to blame him, as he has four stomachs.
Many aliens on Ben 10:
- Just for starters, there's the one that's made entirely of living crystal, which it can fire as a weapon and shape into weapons and tools. Or the one that's on fire... and catching a cold turns it to ice. And then there's Ghostfreak, whose species is weird even by alien standards.
- As if things can't get weirder, humanity is an example of bizarre biology in the Ben 10-verse; we're the only species in the galaxy that can interbreed with pretty much any other species. No one knows how or why, but it happens. This includes Pyronites, who are on fire and whose home world is a freaking sun. Except not really, the guy who was supposedly half-Pyronite eventually turned out to be a full-blooded human who was subjected to horrific experimentation to give him the powers of a Pyronite, then was given Fake Memories of his parentage to keep said experimentation a secret, presumably because the writers eventually realized the glaringly obvious obstacle preventing a human from properly getting it on with a Pyronite.
Final Space:
- Tribore switches between "goods" every six months. Also, his species apparently gives birth through their back, are born from eggs, grow to adulthood within seconds after they hatch and can gain clothes and even weapons seemingly out of thin air as they do.
- From what we see of Bolo, the Titans posses hundreds of "brain chambers" which seem to be entire planes of reality in their own right.
Futurama:
- The show has fun with this quite often when dealing with the crustacean life-form Dr. Zoidberg. Losing organs is merely a minor nuisance for him. In "Roswell that Ends Well", he manages to keep up a running commentary during his own dissection ("Removing the heart." "Take, I've got four of them!"). In the Fountain of Youth episode "Teenage Mutant Leela's Hurdles", he regresses through an improbable number of larval stages, including a cuttlefish stage ("Hooray, I'm a teenage heartthrob again!"), a trilobite stage, and a coral stage where he and several other larvae budded off of a single coral. In an inversion, the Professor states that Dr. Zoidberg's incompetence as a doctor is because, to him, humans have a bizarre biology that he doesn't understand, and he is known as an incredible doctor for any species but humans.
- Kif Kroker (the second-most-often-recurring alien) is a member of an amphibious species with a camouflage reflex, a fluid-filled bladder system instead of a skeleton, and a bizarre reproductive system that causes him to become pregnant from holding someone's hand. His species also begins life as a tadpole, develops into a humanoid adult, and spends the final stage of their life as a swarm of flying hookworms — a transition that is apparently instantaneous, as another member of his species is seen "popping" and transforming instantly into a cloud of hookworms. He also has three nipples and an inexplicable belly-button. How would someone who was born from an egg have one?
- And that goes without mentioning all the other bizarre aliens in the universe including (but not limited to): giant bouncing balls, adorable three-eyed creatures that poop dark matter, the floating brains they fight, a tentacled jelly creature affectionately know as the "Horrible Gelatinous Blob," and a race of water beings. Of particular note is an episode surrounding the "Miss Universe" pageant which includes a, shall we say, diverse variety of beauties.
Gravity Falls:
- Bill Cipher is a triangle with one large eye, tiny black limbs, and no other visible bodily features. This means he doesn't have a mouth, right? Well...not exactly. His eye doubles as his mouth.◊ Also, his top hat is actually part of his body.
- Mermando, a merman, mentions that his voice changed when he was three and that he has "like, seventeen hearts. Horrifying but true!"
Bip in Here Comes the Grump. He can detach his nose, and he turns around by pulling his head and tail into his body and popping them out again on opposite sides.
The titular character of Invader Zim has red eyes, green skin, pink teeth, a pair of antennae, only three fingers on each hand, depends on his backpack for survival, and his only known internal organ is called a "squeedlyspooch". Water is (was) acidic to him and he can grow hypnotic pimples. And then there was that "molting" thing that happened during the Galactic Equinox, when he suddenly turned into a giant mass of pulsating pustules that erupted in a sea of green pus.
Cathy Smith and her grampa in Monster Buster Club look externally human; she is a peppy blonde ten-year-old and he a hunchbacked old man with a big bushy mustache. When not posing as humans, however, they appear to be some kind of mutant hybrid between a flies and fish. Also their bones are made of rubber. They're good guys, though.
Played for Laughs in The Owl House's Hooty, who's biology seems to become more bizarre and unsettling with each episode. He is attached to a door, yet can apparently stretch as long as he needs to in any directon. His mouth can open to the other side, but it also has a throat lined with teeth and another face at the end. The entire house he's in apparently counts as his body, to the point where he can "point" with the weatherwane, and feels it when someone hits the walls. He can also detach his face from the house, though he needs another house-like object to bond to. The way he does this is not seen, but is disgusting enough to make Luz gag and King cry, and it leaves behind visible organs. Finally, he can remove his skin (apparently to wash it), leaving himself as an owl skull at the end of a very long neck.
On Planet Sheen, Glimmorians like Sheen's replacement love interest Aseefa look like blue-skinned elves with Prehensile Hair, but have a symbiotic bond with a uvula-like creature called a "roove". If it's removed, the Glimmorian loses their ability to yodel, suffers extreme impairment to their direction sense, and begins belching constantly and uncontrollably, graduating from clouds of noxious-smelling green fumes to burping flames at random. This can all be cured by simply letting the Glimmorian swallow their roove again.
Rocky and Bullwinkle: In the "Metal Munching Mice" arc, when Gidney and Cloyd explain that they were tricked by the "Big Cheese" (Boris) into making the titular robots.
Gidney: We didn't know our Moon Mice would be used this way, Rocky.
Cloyd: No, cross my hearts!
Bullwinkle: Hearts? You got more than one?
Cloyd: On the Moon, we always carry a spare heart.
In Scary Larry, Carl can make his nervous system glow and turn the rest of his body transparent.
Solar Opposites: Gooblering. Or the Shlorpian equivalent to sweating where they pop out small creatures called Gooblers when under extreme stress. Apparently, too much Gooblering will cause Shlorpians to overheat and die. Before that they might cough up a rare red goobler, which is larger and is driven to torment the parent shlorpian until the stress turns their brain into a baby, killing them.
- They can also taste with their feet. They like to flavor their sidewalks back on Shlorp.
- The children got to choose which gender they would become at a certain point.
The Gems of Steven Universe are literally crystal lifeforms that create humanoid forms as a matter of convenience. They can retreat inside the gemstone itself to regenerate (making them functionally immortal as long as the gem itself isn't cracked), summon weapons and energy, and even fuse into a stronger entity with no upper limit on fusions. They can eat and sleep, but do not need to, and they have no concept of age for themselves, since their physical age is based on personality rather than time. The gems themselves also have unique abilities, anywhere from future vision to holographic projection.
Starfire of Teen Titans (2003). Among other things, she can learn any language instantly through physical contact with a native speaker (kissing seems to be way to do this), and goes through a very weird form of puberty that she has no idea how to handle, as hers involves steadily metamorphosing increasingly hideous features before she enters a giant chrysalis (in comparison, her sister just turned purple for a few days). She drinks mustard the way people drink soda. There's also the business with her having an elongated, prehensile tongue and nine stomachs.
Starfire: Never have I been so glad to have nine stomachs.
Transformers are a race of sapient machines, hence it might not even be proper to refer to what's inside them as "biology" at all. Their inner workings still often get referred to, however, as well as other things that have a biological equivalent.
Rattrap: What's with you two? Is my gearbox hanging out or something?
- Not to mention that they are "born" from blanks made, probably, of nanomachines (though that's a later addition), and their Sparks can be transferred into new bodies.
  - This has led to a lot of fans assuming that "gender", as far as the term applies to sentient robots, is more affectation than anything, and that all that's required for reproduction is a constructed body (at most; some postulate that a "pregnant" Cybertronian can also grow a new body as well as generate a new Spark) and two Cybertronians. Any two Cybertronians.
  - Actual canon meanwhile, has gone even farther in the "gender is purely decorative" area, demonstrating that all you need to create a new Cybertronian is a blank body and the local MacGuffin (Vector Sigma node, Creation Matrix, or Allspark, depending on the universe). Pregnancy doesn't even factor in, and their reaction to finding out how bizarre our biology is, is about what you'd expect the reaction of someone who reproduces by MacGuffin to be if they heard how fleshlings reproduced◊.
- The G1-series' Quintessons had five faces arranged radially, and seem to have been cybernetically-modified organic life forms rather than pure robots.
- The Transformers: Prime Cybertronians actually use the word "biology" when discussing their bodies and physiology. They also claim to have veins.
- As far back as the original series, they are shown to sustain themselves on liquid Energon by drinking it. Even when they're purely mechanical, they still have a sort of bionic anatomy that acts as a digestive system.

Bizarre Alien Biology

Categories of aliens that may display Bizarre Alien Biology:

Some specific types of Bizarre Alien Biology:

Examples that don't fit in the above categories:

Video Example(s):

Zoidberg

Alternative Title(s): Bizarre Nonhuman Biology

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Zoidberg

Bizarre Alien Biology

Edit Locked

Categories of aliens that may display Bizarre Alien Biology:

Some specific types of Bizarre Alien Biology:

Examples that don't fit in the above categories:

Video Example(s):

Zoidberg

Alternative Title(s): Bizarre Nonhuman Biology

Previous

Index

Next

Zoidberg