The Joker first appeared in Batman #1 way back in 1940. Ever since he and Batman have pretty much been joined at the hip, and the Joker has arguably become the world's most iconic comic book villain as well as one of the most famous villains in all fiction. With that in mind, it should come as no surprise that over the years he's stepped out of his comic origins to appear in live-action movies, animation, and multiple video games.