Sonic the Hedgehog is a video game franchise created by Yuji Naka, and is developed and owned by Sega. The franchise centers on a series of speed-based platform games, but several are spin-offs in different genres. The protagonist of the series is an anthropomorphic blue hedgehog named Sonic, whose peaceful life is often interrupted by the series’s main antagonist, Doctor Eggman. Typically, 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 the series, published in 1991, was conceived by Sega’s Sonic Team division after Sega requested a mascot character; the title was a success and spawned sequels, and transformed Sega into a leading video game company during the 16-bit era in the early to mid-1990s. Sonic Team has since developed many titles in the franchise. Prominent members of its initial staff included Naka, character designer Naoto Ohshima, and level designer Hirokazu Yasuhara.