When this prankster buys an enormous number two-shaped balloon, he plants it in unlikely places and finds the opportunity to ask strangers:
"Do you mind if I take a number two here?"
While the jokes pretty crude, the faces of those being pranked are priceless. They have no idea how to respond when someone breaks every rule in the social handbook.
This is the best kind of prank: simple, easy and with a grade school child's sense of humor.
Be careful, or they'll take a number two somewhere downwind of you.