The Joker is a fictional character, a comic book supervillain appearing in DC Comics publications. The character was created byJerry Robinson, Bill Finger and Bob Kane, and first appeared in Batman #1 (Spring 1940). Credit for the character's creation is disputed; Kane and Robinson claimed responsibility for the Joker's design, but acknowledged 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 his comic book appearances, the Joker is portrayed as a criminal mastermind. Introduced as a psychopath with a warped, sadistic sense of humor, the character became a goofy prankster in the late 1950s in response to regulation by the Comics Code Authority, before returning to his darker roots during the early 1970s. As Batman's nemesis, the Joker has been part of many of the superhero's defining stories (including the paralysis of Batman's ally, Barbara Gordon, and the murder of Jason Todd, Batman's ward and the second Robin). The Joker has had a number of origin stories during his seven decades in publication. The most common has him falling into a tank of chemical waste which bleaches his skin white, turns his hair green and his lips bright red; the resulting disfigurement drives him insane. The antithesis of Batman in personality and appearance, the Joker is considered by critics to be his perfect adversary.

One of the most iconic characters in popular culture, the Joker has been cited as one of the greatest comic book villains and fictional characters ever created. He appears in a variety of merchandise, such as clothing and collectable items, real-world structures (such as theme park attractions) and references in a number of media. The Joker has been Batman's adversary in live-action and animated incarnations, including the