Dunk Clown
A dunk clown is someone you hire to show up and publically beat someone you dislike at a thing they believe they're good at. Traditionally it's an actual clown coming to beat someone at basketball, but can be used for any activity.
Smug ass Marvin thinks he's so good at chess, I'm gonna get a dunk clown to take him down a peg.
dunk the clown
name of a carnival game co-opted as secret code used by closet homosexual Mormons to describe their desire to insert their penis in anuses
"I'd really like to find 'dunk the clown'"