I remember watching an episode of a cartoon on TV sometime between 2009 and 2013. I don't remember what channel I was watching it on, but it was almost certainly a rerun.
In it, a character who was missing an arm (or perhaps just a hand) had a prosthetic arm given to him by one of the other characters. The arm then for some reason turned him evil, with the end of the episode having the characters removing the prosthetic from him (and maybe destroying or sealing it).
Does anyone know the name of this show?