Dr. Ivo Robotnik, adopting the better-known alias of Dr. Eggman during Sonic Adventure, is the main and recurring antagonist of the Sonic the Hedgehog series. With an IQ of 300, he is a scientist whose brilliance is used for achieving his vision of dominating the world under his will and direction; a goal that puts him at odds with his archnemesis, Sonic the Hedgehog. Their encounters and battles throughout the years have eventually spanned across both time and space, from the emptiness of Whit.