Best shop practical jokes

[partsman103]

a couple of our techs love to sell/trade items with one another.
one of them sold some A/C window units to the other and guaranteed that they all worked. Well only 1 turned out to be operational.
Both would claim that the other owed them money. We fabricated a fake Attorney letter head and mailed it to the tech that bought the faulty units. (registered mail and sent the letter to the dealership)
The letter stated that if the amount owed was not paid in full, legal action would be the next step and he would be served papers at the dealership, a lean would be placed on his house, tools, and vehicle.
He went ballistic and his reaction to the letter was a kodak moment.