Sega's flagship franchise and one of the most popular video game properties of all time.

This platforming plethora of ring-collecting and badnik-charging stars the titular Sonic the Hedgehog, a real cool blue dude with Super-Speed and a knack for taking whatever thrill rides he can find. Opposite to the blue blur is one Dr. Ivo Robotnik— better known as Dr. Eggman— a mustached Mad Scientist with a big girth, bigger robot army and an even bigger ego, and a life goal of using his scientific know-how (with unique power sources like the Chaos Emeralds being a plus) to achieve world domination. Naturally, the free-spirited Sonic doesn't approve of Eggman's ambitions, and Eggman really hates that hedgehog for expressing said disapproval through scheme-thwarting time and time again, so the series follows wherever the endless conflict between fat man and kinetic Funny Animal will take them next.^note Incidentally, despite being called "Emeralds", only one of them is green. (There are only two games where this is not the case — Sonic Spinball, where none of them are green (they're all blue instead), and Sonic Battle, where all of them are green. In both cases, it's merely Gameplay and Story Segregation — the developers just lacked the time or drive to make different-colored sprites for all of the Emeralds.)

Since Eggman's always striking back with another new trick up his sleeve, Sonic's usually got some help in the form of his supporting cast, including: Miles "Tails" Prower (as in "miles per hour"), a two-tailed fox kit serving as Sonic's trusty sidekick and Heli-Critter transport; Knuckles the Echidna, Sonic's hot red foe-turned-friend with the physical power to match his namesake; Amy Rose, his love-struck Fangirl with a Genki Girl attitude and a mallet you don't wanna mess with; and the cavalcade of all the other friends and allies he's made over the years.

Originally created in 1991 for the then-fledgling Sega Genesis (and not-so-fledgling Sega Master System) by a group of fifteen people (who were later to be named Sonic Team) tasked with creating a mascot to compete with the face of video games, Sonic quickly became the gaming company's mascot, immediately replacing Sega's previous mascot, Alex Kidd. The spunky, ever-lovin' cobalt-blue insectivore grew in strength and speed with each sequel to put its creators into a healthy competitive spot with Nintendo (and other, lesser gaming companies, most notably Hudson Soft and SNK) during the 16-bit Console Wars.

The games were positively brilliant. The sprites were incredibly well-drawn, the levels were huge and expansive with a few alternate paths, and they incorporated many design features like loops, corkscrews, and crumbling ledges that were never seen before in any game. Many entertainment companies were given the license to produce no less than four cartoon series, seven comic series, countless books, a Sunday comic strip, and even an OVA, all to capitalize on Sonic's success. For a short while, Sonic managed to overshadow Mario, Mickey Mouse and even Bugs Bunny themselves in worldwide popularity, due to the technical whizziness of the series' concept (helped by Sega dropping the term "Blast Processing" into its ads) and the proto-Badass nature of its main character. (This was the predecessor to the eventual family-friendly versus mature games debate, with a hedgehog with an attitude standing in for killing beeyotches.)

Of course, SEGA's success with Sonic did not by any means go unnoticed by their competition, both in the West and in their home court of Japan, and in the wake of the release of the original trilogy for the Genesis, a slew of Mascot with Attitude platformers would hit the video game market. Most mascots might have taken the form of more or less subtle imitations of Sonic, but they were all pretty blatantly meant to cash on the series' popularity. These imitators would continue to be a somewhat dominating presence on the video game market throughout the rest of The 16-bit Era of Console Video Games, and the popularity of the subgenre would first truly start to wane in the late 1990s, even with how other big names like a certain bandicoot or dragon took inspiration from it.

Sonic, meanwhile, reached an Audience-Alienating Era during the run of SEGA's Saturn console, which was a good deal less successful than its predecessor. The spinoff game, Sonic R, was the only noteworthy Sonic game on the console. Sonic X-treme was announced, but it was cancelled due to a permission dispute between developers, and filled in at the 11th hour by an upgraded port of the Genesis game Sonic 3D: Flickies' Island.

Around the turn of the millennium, the series got revitalized in a truly three-dimensional incarnation on SEGA's final home console, the Dreamcast. Sonic Adventure and Sonic Adventure 2 were noted for their production values, larger scope and ambitious plotlines, but also criticized for questionable choices and other teething problems; such as the screwy camera and awkward controls usually found in platformers that tried to make their first jump to 3D. Still, both Adventure games were reasonably successful for their time, with the first being the highest-selling title and resident Killer App for the Dreamcast, and the second's port of Sonic Adventure 2: Battle being the highest-selling third-party game for the Nintendo Gamecube, bringing in a massive slew of new fans in the process.

Following Sega's transition to a third-party developer in the early 2000s, Sonic Team attempted to address the Adventure games' concerns with Sonic Heroes, which focused more on team-based gameplay and less on story. The physics, graphics, and gameplay of its successor Shadow the Hedgehog also drew some ire, but it mainly received criticism for its melodramatic story and dialogue.

And then came the game simply titled Sonic the Hedgehog, usually referred to as Sonic the Hedgehog (2006) or "Sonic '06", which was released in late 2006 for the Xbox 360 and early 2007 for the PlayStation 3. By forcing the game out for a Christmas release, what was yet another attempt to undo the issues with the series's Video Game 3D Leap became an Obvious Beta that accentuated the issue. Among the game's many criticisms was the Havok physics engine and loading times reaching lengths that hadn't been seen in almost a decade.

As the ire towards the 3D Sonic games reached its peak, Sega went for a simpler route with Sonic Unleashed in 2008, getting rid of much of the main cast and completely revamping the gameplay to a simpler style involving "boosting", much like Dimps' 2D Sonic Rush series, while pairing it with a completely different gameplay style for variety. The tone was also considerably lighter than the progressively serious tone that characterized the previous games. Unleashed received a mixed reception for the latter style, but it was considered a step in the right direction for giving the series the exhilarating speed experience it needed and addressing much of the problems that previous Sonic games had.

Sega listened to the reception and refined the boost-centric gameplay for the Nintendo-platform-exclusive Sonic Colors in 2010 and the milestone-celebrating Sonic Generations in 2011, further reducing the prominence of the large cast and lightening the tone to a more humorous Saturday morning cartoon-like tone. Sonic Lost World continued the latter trend, but introduced a completely new Super Mario Galaxy-inspired gameplay style, which had led many to ponder if Sega went too far with the Lighter and Softer trend just as they did with the Darker and Edgier trend before. Despite this, Colors and Generations were both viewed as some of the best games that the franchise had in years, with the latter having strong sales and an active modding scene even a decade later.

In 2017, Sega released Sonic Mania, a new 2D side-scroller done in the style of the original 16-bit games. Developed by long-time fans and former romhackers, and using an engine and style replicating the feel of the original games, the game has received wide critical acclaim, essentially made up for previous attempts to bring the classic 2D gameplay back and, at least for the time being, creating a lot of goodwill for the franchise once again. However, on the 3D side of things, Sonic Forces attempted a return to the boost gameplay and more serious storytelling, but received middle-of-the-road reviews for its short length and heavily linear gameplay, despite its Character Customization feature being widely praised.

Sonic Team would take the reception of Forces to heart, and set out to make their next game the best they could. The end result of their efforts, Sonic Frontiers, would release in 2022 and receive much more positive reception, with fans and most reviewers praising its emphasis on open world exploration and combat, and a much more involved story compared to Forces, quickly becoming the best selling title in the series since its 90s heyday.

As mentioned, some titles in the series have been notable for suffering mixed-to-negative critical reception. In line with all the controversy, large varieties of theories exist to explain why the Sonic series is struggling in terms of reviews, such as hastened development for deadlines, no talent or caring from the development team, over-reliance on "overgimmicky" gameplay styles or features, taking the series in too dark a direction, unpleasable demands from nostalgic fans, or the inability to give the franchise a concrete identity.

Nevertheless, the series remains massively popular and beloved by many in spite of the above controversies. Do not let all that has been stated above fool you — beyond all the disappointments, the constant jabs, and the notorious fanbase, people still love Sonic the Hedgehog.

A feature-length Live-Action Adaptation based off the franchise was also released by Paramount in 2020, after having been stuck in Development Hell since the 1990s. Neal Moritz of The Fast and the Furious fame and Tim Miller of Deadpool executive produced this film, while Jeff Fowler, best known for the 2004 short Gopher Broke, made his feature film directorial debut. In spite of an earlier controversy regarding Sonic's original design for the movie (which was later redesigned in response with input from veteran Sonic artist Tyson Hesse), the film released as a hit with audiences and the box office, being widely acknowledged as avoiding the issues of most video-game-to-film adaptations, and launching a sequel in 2022, with a third movie and a spin-off live-action series currently in development.

Sonic has also appeared in every Super Smash Bros. game since Brawl.

Games and other media featuring Sonic:

Tropes throughout the franchise:

• Tropes Numbers-B
  • Big Bad
• Tropes C-E
• Tropes F-L
  • Gratuitous English
  • Guide Dang It!
• Tropes M-R
  • Mythology Gag
• Tropes S-Z