Clowns

The Evil Clowns or Jesters are a villain archetype made famous by the Joker, but also stemming from the natural fear of clowns many experience as children and for some people go past their childhood. Most evil clowns in fiction are either completely psychotic homicidal maniacs, or particularly malevolent tricksters and pranksters. Often, they are both. Evil Clowns are also invariably portrayed as being sadistic and many are also emphasized as not even being human but rather some kind of lovecraftian horror.

Needless to say given all of the above as well as their typically frightening appearances, incredibly violent nature, and high likeliness to cross the Moral Event Horizon, they are often shown to have little to no redeeming qualities of any kind. Clowns are funny villains.