Doctor Ivo "Eggman" Robotnik is the main antagonist of Sega's Sonic the Hedgehog series. Eggman was created and designed by Naoto Ohshima as part of many design choices for Sega's new mascot. After the creation of Sonic the Hedgehog, Ohshima chose to use his previous egg-shaped character to create the antagonist of the 1991 video game Sonic the Hedgehog, making him the arch-nemesis of the series' eponymous main character.