This trope is under discussion in the Trope Repair Shop.

In Speculative Fiction, being a clone absolutely sucks. It's enough to make a clone sing the blues.

Though Real Life clones are simply the equivalent of identical twins produced artificially instead of naturally, have to start at conception and go through childhood at the usual speed to reach adulthood, and can even have phenotypes that vary from their genetic source, Speculative Fiction clones are like perfect meta-xerox copies of the cloned person. They are exactly like the target at the moment of cloning (possibly excused by age acceleration), with all their forebears' memories and skills, although their personalities can develop from there.

As a result, many clones brood about how they're not "real," just hollow imitations of the original. The clones tend to deal with this rather badly. Some make desperate attempts to act different. Others go mad and try to murder the original to take their place. (Emphasis on "try" — hardly any succeed.) If the clone is a main character, they will spend the whole show angsting about how they're the Tomato in the Mirror. Occasionally they will have powers just like the Artificial Human. This often just ups their feelings of alienation, though. This, of course, only works with artificial clones that are identical to the original; natural identical twins are clones as well, the difference is that twins don't have the exact same memories, personality and relationships as the other (and neither do artificial clones in Real Life).

That's for the lucky clones who are created properly. In many shows, cloning is an imprecise science, so there is a high probability that any clone will turn out to be an Evil Twin — almost as high as the probability of creating an evil computer (because everyone knows that Science Is Bad). Other unlucky clones will just have birth defects, Resurrection Sickness, or be increasingly inexact duplicates.

And that's for the clones who are just unlucky. The really unlucky clones have malevolent creators who can make custom clones grown in a vat, sometimes in bulk — which are exact meta-xerox copies of the original except that they have fanatical loyalty to the creators. You can expect all that tinkering to make something Go Horribly Wrong, too. A clone like this is always considered highly expendable by their creator, except in rare cases where said Evilutionary Biologist has developed an attachment to it.

Because of all this (or possibly as a cause of all this), clones get very little respect. Heroes who hesitate at killing intelligent life might still kill their evil clone. In the question of What Measure Is a Non-Human?, most clones rank somewhere between the Big Creepy-Crawlies and the Mecha-Mooks. Interestingly, on the question of What Measure Is a Non-Unique? the only clone that matters is the last one... provided the original is dead.

This assumes the clone ever had a mind of its own, of course. Sometimes a clone is an Empty Shell without the original's soul, and exists only so that the creator can overwrite their mind and personality onto it in case of accident. In this case, it's more like coming Back from the Dead — although if the clone has a mind of its own at the start, this is yet another reason its life sucks. And let's not debate how Our Souls Are Different, in which case clones (especially of the deceased) will be soulless abominations before God and nature.

Some clones aren't traditional biological clones at all — they're robot doubles, or the fruit of a Brain Uploading, or time travel duplicates, or copies created by the good old transporter. These have more reason to be exact xerox copies — but they get even less respect.

Sometimes a story resolves the issue by having the original and the clone(s) fuse "back" into a single being. This is seen as a way to solve their problem without anybody dying. How much logical sense it makes that this would be possible depends on what flavor of Applied Phlebotinum was used to make the clones, but it's common to see this solution used even when the clone was clearly not physically "split" off of the original.

Note that all instances of actual cloning in Real Life require a live animal of the same or similar species with a womb to carry the cloned animal to term. Science fiction tends to ignore this requirement competely, which only enforces the Trope.

See also Scale of Scientific Sins, Creating Life, Identity Breakdown, and Existential Horror. Closely related to Expendable Clone. Contrast with Clones Are People, Too, where they do get to live their own lives. One of the most common sub-tropes to Supernatural Angst.

Warning: This trope is often introduced as a Plot Twist, so expect spoilers.

Examples: