[Hated trope] When a villain is meant to be taken seriously, but are so unnecessarily evil they end up becoming funny.

The Painter - Urbanspook

A serial killer with multiple victims including children and who creates abstract paintings of their victims, but they murder them in so comically exaggerated and complex ways they appear satirical at times. (The dude legit hung a fucking two month old for crying out loud)

William Afton - FNAF

A child killer and mad scientist with dozens of victims in all media and whose obsessed with becoming immoral, runs experiments using hallucinogenic gases on children, built his robots to be efficient in child catching and killing, murdered his own best friends child out of spite, and was so wicked he left behind an agony being created from all the negative emotions he created who became a killer themselves.