There is some truth in what you say. However, I have seen the idea of the killer clown more than once. My favorite anime show happens to be hunter x hunter. However, they never show his backstory. He's a deceptive character and killer. A merciless clown that wants only the strong to survive that can put on a fight. Which makes him an interesting character. He kills weaklings in the story. As he doesn't think they deserve to live.