Sometimes, villains are just pawns of other villains, which is the example of Aaron Helzinger, aka Amygdala. During a homicidal rage, he was taken to surgery to have his amygdala removed in an attempt to calm him down. But this comic book land...so it had the opposite effect. Now, Amygdala has near superhuman strength, which only gets enchanced when he's angry.
This has made him the perfect pawn of numerous Batman villains, and though Batman has taken him down before, it's not without a fight.