Fan Casting Beware the Silly Ones in Sort by Tropes

So you've got a person who might fulfill the role of comedic relief. For the most part, both the fans and the characters in-story see them as just a great big doofus. Possibly, they spend more time acting ridiculous or laughing in the face of Serious Business than getting dangerous. Sure, they might rant up and down about how they're going to conquer the world in the name of Evil with a capital E or drive the villains to suicide through bad jokes, but in the end they seem to pose little threat to all present.