I bring this up because after watching Bakos24's seafoam video it brought back some memories. I worked as an auto mechanic for about 11 years and was always pranking coworkers.Anyway there was an older tech there who everyone always screwed with.One day he was prepping a new van and while he was washing up for a test drive I pulled a vacuum hose and let the engine suck in a little "lubrication" into the intake .Needless to say when he got back from his test drive he thought he blew up the engine it smoked so bad. Another time a factory rep was visiting our store and he and the boss went out to lunch.I went out to his vehicle,popped the hood and ran a jumper wire from the turn signal relay to the output wire to his horn.After he left it was about 10 minutes and he was back with this strange problem of his horn honling while his turn signals were on . Guess who they go ask about that problem? . Everyone got a good laugh out of that. One more good one is on some import cars the tip of the exhaust pipe is rolled.Get a good strong ballon and put over that lip and stuff the excess in the pipe.They start the car and start driving off and BOOM!!! WTF they are thinking..... Anyway,what are some of your pranks you have pulled ???