The Joker

The Joker is a supervillain appearing in American comic books published by DC Comics. Created by Bill Finger, Bob Kane, and Jerry Robinson, the character first appeared in the debut issue of the comic book Batman on April 25, 1940. Credit for the Joker's creation is disputed; Kane and Robinson claimed responsibility for his design while acknowledging Finger's writing contribution. Although the Joker was planned to be killed off during his initial appearance, he was spared by editorial intervention, allowing the character to endure as the archenemy of the superhero Batman.

In the DC Universe, the Joker is portrayed as a criminal mastermind and the antithesis of Batman in personality and appearance. He was introduced as a murderous psychopath with a warped, sadistic sense of humor but became a comical prankster in the late 1950s in response to regulation by the Comics Code Authority, before returning to his darker roots during the early 1970s. The Joker has been part of defining Batman stories, including the murder of Jason Todd—the second Robin and Batman's ward—in "A Death in the Family" (1988) and the paralysis of Barbara Gordon—Batgirl—in The Killing Joke (1988). Unlike many comic book characters, the Joker does not have a definitive origin story, but various possible ones have been developed. The most common story involves him falling into a tank of chemical waste that bleaches his skin white, turns his hair green and lips red, and leaves him with a rictus grin; the resulting disfigurement drives him insane.