Sonic the Hedgehog is a video game character and the protagonist of the eponymous video game series released by Sega, as well as in numerous spin-off comics, cartoons and books. The first game in the franchise was released on June 23, 1991, in order to provide Sega with a mascot to rival Nintendo's flagship character Mario (see 1991 in video gaming). Since then, Sonic has become one of the world's best-known video game characters, with his series having sold 50 million copies. In 2005, Sonic was one of the first game character inductees into the Walk of Game, alongside Mario and Link.
Artist Naoto Ōshima, designer Hirokazu Yasuhara and programmer Yuji Naka are generally credited with the creation of the character, a blue-haired, mostly blue-skinned 15-year-old anthropomorphic hedgehog, who has the ability to run faster than the speed of sound and the ability to curl up into a ball, primarily to attack enemies. This is a major part of the gameplay of the series.