Pranks are fun, especially when they're harmless and really easy to do. This prank worked out well because the guy who's washing his hair conveniently faces the wall, oblivious to what is going on behind him. Just as he's about to get the shampoo out of his hair, his "friend" adds more, creating a vicious but hilarious cycle.

What kind of pranks do you play on your friends? Do they turn out this well?