We doubt that's this Charlie's secret but it's often true in films that you simply cannot trust your uncle.
Take Hamlet's wicked uncle, Claudius, whose dastardly plan has inspired more than one cinematic villain's plot to seize power. Of course, Shakespeare also drew from real life, since murderous uncles and young heirs unfortunately go hand in hand. And then there are those uncles who get away with a different kind of murder, whether it's neglect or outright abuse.
Here are 12 of the creepiest, no-good movie uncles we could find.
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Gallery | Creepiest Movie Uncles
(Need a creepy uncle antidote? Check out "Secondhand Lions," in which a gruff Michael Caine and Robert Duvall take in neglected nephew Haley Joel Osment or "Unstrung Heroes," where a boy's eccentric uncles help him through his mother's illness.)