The Toxic Avenger (1984)

It tells the story of a mentally retarded young man who is a mop cleaner in the fitness center. one day, he was played and became the laughingstock of the public. He accidentally fell from the glass window upstairs and accidentally fell into some kind of waste water used in the chemical industry. His body was seriously damaged by radiation, and his gene mutation became a half-monster. He decided to take revenge and declare war on the evil forces of society.