Sonic the Hedgehog is a videogame franchise created and produced by SEGA. The franchise centers on a series of speed-based platform games. The main character of the series is an anthropomorphic blue hedgehog named SONIC, whose peaceful life is often interrupted by the series' main antagonist, Doctor Eggman. Sonic—usually along with some of his friends, such as Tails, Amy and Knuckles—must stop Eggman and foil any plans of world domination. The first game in series, released in 1991, was conceived after Sega requested a mascot character. The title was a success, it spawned many sequels, and it transformed Sega into a leading video game company during the early to mid–1990s.