Doctor Heinz Doofenshmirtz

Doctor Heinz Doofenshmirtz (also known as Dr. Doofenshmirtz, or simply Heinz) is a scientist who formerly worked under Doctor Eggman. Heinz's loyalty has fluctuated throughout the series, working on his own accord in Sonic Hedgehog 2: Eggman Strikes Back, with Doctor Nefarious in Sonic Twinsanity and even returning to Eggman's side in Sonic: Mind Over Mutant.