User blog comment:Bionicleboy3000/Metal Sonic: The most overpowered robot in fictional existence?/@comment-3437898-20130107153258

I'm surprised you didn't use Metal Sonic Kai from Knuckles Chaotix, but I assume it wasn't used because you never played the game (neither have I) or you consider it non-canon. On a slightly unrelated note, wasn't Cell from Dragon Ball Z a robot (labelled as android), he seemed as capable of wiping out all existence if it weren't for Goku (or whoever killed him).