"Keying" a car is more than your run-of-the-mill vandalism. It's the same as any other serious offense. To be convicted, a prosecutor must prove that you have committed this type of vandalism. This means proof that you intended to cause physical damage to the vehicle, specifically to someone else's property.
Vandalism sounds like a minor criminal offense, but that depends on the actual crime. Over in Daytona Beach, FL, police arrested a man for beating an ATM with a hatchet. You certainly don't hear that everyday. His alleged act of vandalism occurred early this past Sunday morning, when the man walked up to an ATM and went psycho on it. Before the surveillance camera was destroyed, it took at three images of the man standing in front of the ATM with a personal check, taking a swing at the machine with his right hand, while holding the hatchet. Police officers identified the suspect from the surveillance photos and he was arrested early Monday morning. He was charged with criminal mischief and burglary to a structure.