"Sonic the Hedgehog (ソニック・ザ・ヘッジホッグ), trademarked Sonic The Hedgehog, is a video game character and the protagonist of the Sonic video game series released by Sega, as well as in numerous spin-off comics, cartoons and a feature film. The first Sonic game 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 more than 70 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 15-year-old anthropomorphic hedgehog, who has the ability to run faster than the speed of sound and the ability to curl into a ball, primarily to attack enemies. This is a major part of the gameplay of the series."
Source: Wikipedia, "Sonic_the_Hedgehog_(character)", available under the CC-BY-SA License.