Heath Ledger turned up, did that, and now every comic book villain is just trying to keep up.
Fun fact: "Heath Ledger locked himself in a hotel room for six weeks to develop the Joker's voice and mannerisms."
Bloke in a giant mouse head who picks fights online and fills arenas, can't really argue with it.
Fun fact: His stage name came from finding an actual dead mouse inside his computer while building it.