Send in the scary clowns
Pennywise from Stephen King's It
Stephen King's horror novel "It" introduced a clown character who came from another world to prey on children and murder people.
The Joker from Batman
Batman's greatest villain is the Joker, a criminal who employs gags and tricks reminiscent of clown performances.
Clown doll from Poltergeist
While technically not a clown, the poltergeist possess a creepy clown toy in the movie, causing many to cite it as a source material for their own fear of clowns.
Clown zombie from Zombieland
After navigating through a bunch of challenges, the protagonist of the movie comes face-to-face with a zombified clown.
John Wayne Gacy
Perhaps the scariest of them all is John Wayne Gacy, a real-life American serial killer and rapist who dressed up as a clown. He sexually assaulted and murdered at least 33 teenage boys and young men.