If you're looking for a simple prank that's sure to freak out innocent passersby, the Fake Arm is sure to do the trick. Designed to look like a real man's arm, you can stick this badboy anywhere and it will definitely inspire a double-take.

Simply tuck the sleeve-end of the arm into your trunk, and watch old ladies at the mall reach for the cellphones. Just don't get to close or you might get whacked by a granny bag. The Fake Arm also works well in cellar doors, under a bed, in a duffel bag, under a garage door, or sticking up from your stuffy neighbor's prize rose garden!