Dr. Ivo Robotnik (ドクター・ロボトニック Dokutā Robotonikku?, lit. "Doctor Robotnik"), better known by the alias Dr. Eggman (ドクター・エッグマン Dokutā Egguman?), is the main antagonist of the Sonic the Hedgehog series. He is a human and the arch-nemesis of Sonic the Hedgehog. This large scientist with an IQ of 300 dreams of dominating the world, but his constant plots to create his Eggman Empire are always thwarted by Sonic and his friends.
While the doctor's plans initially consisted of building incredible armies by turning animals into robots and using them to dominate the land, Dr. Eggman's schemes have since branched into much more global threats as he built war machines, used nuclear devices to threaten entire nations, and even relied on mythological and ancient deities bent on destruction to achieve his goals. Eventually, the mad scientist has gone as far as to target the entire universe and cooked up schemes to control time and space itself.
While all these plans end in failure thanks to the continued efforts of Sonic and his friends, the mad doctor is somehow always able to slip away from certain death or imprisonment and escape at the last moment, making him a constant threat to the universe and a thorn in Sonic's side.