Sonic the Hedgehog

Sonic the Hedgehog was a video game.

History
In 1989, Alistair Gordon Lethbridge-Stewart was aware that the titular character was a blue hedgehog. (PROSE: Business Unusual)

Mel Joseph was playing the game on his computer, completing the Scrap Brain Zone. (PROSE: Conundrum)

Mickey Smith had a copy of the game on either his Playstation or Xbox, along with Grand Theft Auto and Gran Turismo. (PROSE: Winner Takes All)

Ace joked with Dr John Watson that whatever the Rakshassi were worshipping, it wasn't Sonic the Hedgehog. (PROSE: All-Consuming Fire)

Behind the scenes
The franchise is one of the many to be represented in LEGO Dimensions, with Sonic himself appearing as a playable character.

While the character is implied to have been around from as early as 1989 in the DWU, in the real world his first appearance was in 1991.

Connections
The Legacy story Sonic Adventure shares its name with. It is not known whether this was an intentional nod.

TT Games and Sumo Digital have developed a number of Sonic or Sonic-related games.

Virgin Books published a series of original novels based upon the series in the early 90s.

Various comic books based upon the series have been published. A series titled ran in the UK from 1993-2002, on whom multiple people also involved with DWU media have worked, the most notable examples being Richard Elson, Lew Stringer, Gary Knight, Andy Diggle, Alan McKenzie, Mike McMahon, Anthony Williams, Steve Cook, Mark Millar, John M. Burns, and Elitta Fell. More recently, began in 2018 under IDW Publishing, with Jack Lawrence among its art team.

References to Doctor Who

 * Among the most notable exclusive villains of the aforementioned Sonic the Comic series were the "Brotherhood of Metallix", an army consisting entirely of s (Sonic's robotic doppelgänger from the video games). Many fans noted similarities between the Brotherhood and Doctor Who's own Dalek Empire, being led by a larger "Emperor Metallix". Nigel Kitching, one of the comics most prolific writers, acknowledged this, stating that he did not intend to "rip off" the Daleks but, after noting the similarity, chose to run with the idea. He further stated that, since Doctor Who was off the air at the time, he believed the similarity was unlikely to jar the series' readership.
 * In issue 52 of ' comic series - which was the final chapter in a multi-series crossover event with the Sonic the Hedgehog franchise - Sonic character Sticks the Badger uses the phrase "wibbly-wobbley" when describing time travel.
 * In issue 19 of the IDW comic series, E-123 Omega, a robot character, is seen exclaiming "exterminate" in a similar fashion to the Daleks.
 * In issue 49 of the aformentioned IDW series, a Dalek figurine can be seen on a shelf in Tails' house.