The Joker is a main antagonist of DC Comics, most recognizably being the archenemy of Batman, having been directly responsible for numerous tragedies in Batman's life, including the death of Robin (Jason Todd, formerly the 2nd Robin, currently The Red Hood) and the paralyzing of Barbara Gordon (Oracle, formerly Batgirl), and was generally one of the most infamous of Gotham's criminal elements. In the comics, the Joker is portrayed as a master criminal whose characterization has varied. The original and currently dominant image is of a highly intelligent and manipulative psychopath with a twisted, sadistic sense of humor.
His most prominent origin story was that he fell into a tank of chemicals, which bleached his skin white, turned his hair green and turned his lips bright red, giving him the appearance of a clown.
His manipulative mind allows him to control the city with the press of a button. He is shown to have a high level of knowledge and is able to comprehend various scientific tasks. The Joker will often claim he never has a plan, but this menace often has a plot drawn out long before he meets the protagonists. His crazed grin, evil, clown-like appearance and sadistic practical jokes all make the Joker one of the most diabolical villains of DC Comics and of all time. He is also one of Superman's recurring adversaries, a dangerous foe to the Justice League, and one of Batman (Terry Mcginnis)'s greatest foes.
He is one of the most iconic and recognized villains in popular media, having been ranked #1 on Wizard's list of the 100 Greatest Villains of All Time.