I STILL think the "Poo on a Stick" is a great idea muhahaha
For some it would be the thought of getting hit by poo would speed them up, and for "ONE" we know they would think of it as Candy
Actually, I don't think punishment is a great idea, but someone mentioned about a Special Race ran by someone not in the game and bestow gifts/or punishment. But instead of Punishment, it could be just a "Silly" thing. I don't know if there is a Universal Message that all empires would get, but something like "The Narrewian Empire just got hit by a Comet of Poo, no life lost, stocks of toilet paper soar!"
Something Silly, nothing visous. Just have fun is all.