Winner sends 3 messy tasks to loser. Loser modifies all 3 to make them worse and sends them to winner. Winner then modifies them again to be worse and sends them back.
Loser then picks one original, one single modified, and one double modified task to do.
Submerge a banana in a bowl of batter. Without using your hands retrieve the whole banana and eat it in less than 30 seconds. If you don't, pour the bowl of batter over your head.