The Egghead
Dr. Ivo Robotnik or Dr. Ivo Eggman is the main antagonist of the Sonic the Hedgehog series and Sonic's arch-nemesis. He is a human mad scientist with an IQ of 300 and a evergrowing army of Badniks. He also is the creator of Metal Sonic and Mecha Sonic. He is always trying to take over Mobius and build an empire known as Eggmanland, which are always stopped by Sonic and his friends.
Mario and Sonic: Worlds in Danger
Dr. Eggman appears as one of the main antagonists of Jmkrebs30's Flash series Mario and Sonic Worlds In Danger, alongside Bowser. He and Bowser plan to bring the Mushroom World and Mobius together by dimensional warping. They also recruit several past enemies of Mario and Sonic the Hedgehog. Such as, Eggman Nega, Dry Bowser, Koopa Bros, Chaos, Phis, Tatanga, and many more. Bowser and Eggman are confirmed to fight Mario and Sonic at the end of the series, with Bowser as Giga Bowser and Eggman piloting the Egg Omega Robot.