Dr. Eggman

Dr. Eggman, also known as Dr. Robotnik, is a persistent enemy and the arch nemesis of Sonic the Hedgehog, much in the same manner as Bowser opposes Mario. The Doctor is a genius with an IQ of 300, and his goal is to dominate the world and build Eggman Empire.

Mario & Sonic at the Olympic Games
Dr. Eggman, as well as several other Sonic the Hedgehog series characters, appears in the Olympic crossover game Mario & Sonic at the Olympic Games. He is a Skill player, despite his rather large size, and he's also unusually fast. However, Dr. Eggman is lacking in power, and his stamina isn't that strong either.

Mario & Sonic at the Olympic Winter Games
Eggman appears as a playable character in the sequel Mario & Sonic at the Olympic Winter Games, and appeared in the first trailer for the game along with Sonic, Mario, and Wario. He is again a skill type character. In the DS version of the game, he is one of two main antagonists of Adventure Tour along with Bowser. He and Bowser try to stop the 2010 Olympic Winter Games by capturing all the Snow Spirits. They would like to make their own Olympic Games, but Mario, Sonic, and their friends have stopped Eggman and Bowser.

Mario & Sonic at the London 2012 Olympic Games
Dr. Eggman appears once again as a Skill type playable character in Mario & Sonic at the London 2012 Olympic Games. He has a very high Technique level and performs well at events such as Gymnastics.

Profile
''Although the devious Dr. Eggman has great Skill-based abilities, he also is quite powerful. His huge, lumbering frame doesn't give the impression that he would be good at gymnastics, but believe it or not, he can handle the trampoline and vault quite well.''

Super Smash Bros. Brawl
Dr. Eggman makes a cameo appearance as a collectible trophy in Super Smash Bros Brawl, which is obtained by collecting over 500 stickers. He also appears on a sticker which increases a character's launch resistance by 39 points.

Trivia

 * Dr. Robotnik, along with Miles "Tails" Prower and Amy Rose, are the only major characters in the Sonic series to have formal names.
 * Dr. Eggman has a bulbous pink nose similar to Wario, Waluigi, Dr. Crygor, Jimmy T., Jimmy P., and Booster.
 * Dr. Eggman will be appearing alongside Bowser in the upcoming Disney film Wreck-It Ralph.