When a very serious pop culture villain, (or evil historical figure) Becomes whacky and silly in a comedy movie. Similar to the “Fish Out of Water” trope but for horrible people.
Mike Stolklassa (In reference to the movie “Bill and Ted” in their re:View episode): “Or you got Napoleon at a Water Park or eating a big thing of ice cream. It’s funny because it’s Napoleon.”
The entirety of the “popular” internet show from 1919 “Chad Vader” is also a very good example of this and is where the term Chad Vader Syndrome comes from.