Eateth on
A loud, obnoxious way of telling someone to go for it, even if they're probably going to fail.
"Eateth on, you lard-burger! I bet you're gonna fall flat on your face!"
"Eateth on, you s***-eating beast! I bet you're gonna win this match!"
"Eateth on, you greasy goblin! I bet you're gonna f*** this up!"