DF Pranks

All that is required for this vicious prank is a flat bladed screwdriver and a real mean streak.
Unscrew the license plates from your victims car. Grab the front and the back plates.

Technically, you cannot drive a car without plates, so the victims car is legally undriveable. They can get a temporary permit, but unless you return the plates (and you really should), they have to get new plates from the state which is a pain.

You can always stash the plates someplace where the victim will easily locate them.