Muscle Man

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Muscle Man is the one of primary antagonists of Regular Show. He resembles a zombie with brown hair. However, he is a human. His real name is Mitch Sorrenstein.

He enjoys bragging, pulling pranks, and annoying Mordecai and Rigby. He is overall, by these actions, viewed as a bully. However, he is a total idiot since he willingly got fired by Benson, but this contradicts the later events that Benson actually lets Muscle Man have lunch during his work shift and gives him an Appreciation Day certificate for "working hard".

Despite his annoying habit of pranking, the episode Prankless revealed that his pranks are actually important to the park. Benson tells about how one of Muscle Man's pranks saved the park from a war with a rival park. In the episode, Muscle Man quits after accidentally injuring Pops with his pranks, bringing the park in peril. Pops later persuades him to pranking again by injuring himself with a boxing glove prank (saying it was from the rival park). This episode reveals that Muscle Man is not such as bad person, as says he enjoys pranks so long as they don't harm others.

Trivia
He look mostly similar to one of left 4 dead's Icon creatures the Boomer with blue shirt, they both look-like zombie mutants put both them are not share connections like boomer more fatter to with fictional disease called "Green Flu" but Mitch look more overweight or sightly obese and suggest got fictional genetic condition that make them green skin and very acting mentally retarded and as well allusion of fat and stupid american stereotypes which usually shown every episode expect "Exit 9B" and couple episodes.