After airing the South Park episode "200", the makers Trey Parker and Matt Stone received death threats from a radical Muslim group.

The episode was lampooning, among other things, the fact that the prophet Muhammad is not supposed to be depicted visually. As a joke the episode depicted a "Muhammad" character dressed up in a bear suit (so that people can't see him).

A website called "RevolutionMuslim.com" placed a warning for the writers of the show, Matt Stone and Trey Parker. The warning stated that Stone and Parker "will probably wind up like Theo Van Gogh" (referring to a Dutch filmmaker who was assassinated over how he portrayed Muslim women.)
(source)