Holy crap! A little bucket of pee was the worst i'd heard of. That guy took it to the next level.
Not a car prank but a good prank. Before my wife and I got married, I helped her get my best friends truck, saran wrap the whole truck with something on it, can't remember what she put on it. So my friend thought it was just her so what he did was get a 50 gallon garbage can and filled it with water and propped it against her front door. I can't remember who opened the door but when they did, 50 gallons of water got all over their floor, which was in an apartment so it was all carpet and they lived in the bottom unit which was 4 feet below the ground level so it didn't escape anywhere. ruined the carpet and some other stuff, her parents were not happy about it, they paid for new carpet I believe. Good prank though that started out by a vehicle prank.