How did the clown in Fatal Joke become an antisocial criminal?

Marvel comics and DC are the main superheroes in American superhero movies. Marvel's superheroes include Captain America, Hulk and Iron Man, while DC's superheroes include Batman and Superman. Batman, a popular hero in DC, has been made into a movie many times. Nolan, a famous Hollywood director, has never surpassed the Batman trilogy, especially the second part of The Dark Knight, and has become the ceiling of a series of superhero movies. No matter from the depth of conception or acting, almost no superhero movie can surpass this one. In this movie, the clown, as an opponent of Batman, has gained countless fans. But the film doesn't tell you the specific origin of the clown, so how did the clown come from?

In the DC cartoon Batman: Killing Joke, the author reveals the origin of clowns for the first time. The clown, like most villains, was an ordinary little character at first, an ordinary person that Batman was willing to give his life to protect. What caused him to become a clown step by step?

The clown was originally just an ordinary employee, but he thought he was humorous, so he quit his job and turned to be a talk show actor. But he can't make up humorous and attractive jokes, so his career is unsuccessful and life is getting harder and harder. Meanwhile, his wife left him. By chance, he came into contact with a criminal gang. They sent the clown to the chemical plant to steal things, and they would pay him 5 million yuan when it was done. Lured by the huge bounty, he sneaked into the chemical plant, but was discovered and accidentally fell into the sulfuric acid pool. After being picked up, his face was destroyed by sulfuric acid. Under various blows, his spirit completely collapsed and the clown was born.

The clown always thought that his disfigurement was related to Batman, so he took revenge on Batman crazily. At the end of the cartoon, Batman and the clown come to the chemical plant. The clown asked Batman to kill himself, but Batman thought the clown could turn over a new leaf and didn't kill him.