This prank has been around for decades and never loses its appeal. A seemingly ordinary and harmless ketchup bottle houses a red string that shoots out and onto your unsuspecting victim. No shirts are stained or friendships ruined with this prank, but its guaranteed to get a few laughs. Take this fake ketchup bottle to your favorite restaurant and fool your waitress or bartender, just make sure they have a good sense of humor or you might end up wearing real ketchup. This is one of those classic pranks that will always get laughs no matter how many times you pull it.