Eat Your Hat
You lost a bet, and now you have to eat your hat like it's the last meal you'll ever have. It's like being forced to swallow a whole pizza with no cheese.
"I said eat your hat when Obama won, and I did.", after losing a bet to his cousin.
"Eat your hat, you idiot!", after betting he'd win the lottery and he didn't.
"Eat your hat, you dumbass!", after losing a bet to his brother.