The Joker's continuing agenda is to humiliate and destroy Batman and his allies. A former hired hand for the mob, he was viciously funny, cruel and sardonic. The Joker first encountered Batman during a botched robbery at the Monarch Playing Card Factory. While he escaped by leaping into a drainage vat of chemical waste, the Joker later discovered that the toxins had bleached his skin chalk white, dyed his hair fluorescent green, and stretched his lips into a hideous, permanent grin.
The Joker is rarely alone. He is generally joined by his main squeeze, Harley Quinn, and his hired muscle Mo, Lar, and Cur.
The Joker would continue to torment Batman. He would even cause trouble for the future Batman Beyond, Terry McGinnis, by taking over the body of one of Batman's sidekick Tim Drake.
Batman's arch-nemesis, The Joker is the worst kind of evil villain. Not only is he smart, devilish and cunning... he's also stark-raving mad! It was an unplanned encounter with a vat of chemicals that turned the Joker's skin chalk-white and his hair bright green. Wouldn't that send just about anyone over the edge? The accident also affixed The Joker's mug with a permanent clownish grin. No wonder he is regarded as "The Clown Prince of Crime." The Joker has been known to commit everything from kidnapping to murder to robbery, but his general strategy is to cause as much mayhem as possible.
And he will stop at nothing if he sees an opportunity to play a fatal joke on Batman. The Joker has developed a number of deadly devices and weapons, but he is perhaps best known for the invention of Smilex, a poisonous chemical gas that freezes a Joker-grin on the faces of its victims. Truly a ghastly concoction. Batman would like nothing more than to lock The Joker in Arkham Asylum, the creepy Gotham mental institution, and throw away the key. But that's the last thing on The Joker's fractured mind. The Joker relies on the aid of Harley Quinn, his lovely but lethal assistant, to plan and execute his twisted plots and schemes.