Doctor Ivo Robotnik (ロボトニック, Robotonikku), also known by his alias Doctor Eggman (ドクター・エッグマン, Dokutā Egguman), is a video game character and the main antagonist of the Sonic the Hedgehog series created by Sega. Dr. Eggman is a rotund mad scientist with an IQ of 300, who plans to conquer the world in order to build his Eggman Empire, and is the archenemy of Sonic the Hedgehog. His original character designer was Naoto Ōshima, and while he has gone through several large appearance changes throughout the series, his in-game designs retain several basic characteristics, such as his egg-shaped body, red-black-yellow clothing, pince-nez sunglasses and large mustache. Most of the time, Dr. Eggman is portrayed as horribly immature: he tends to throw temper tantrums when he fails or is offended, despite his incredible intellect and skilled mind. He has appeared in almost every Sonic the Hedgehog video game since his first appearance in the 1991 title Sonic the Hedgehog, and is also a prominent character in other Sonic media, including comics, novels, animated TV series, and an Original video animation.