re: What's the best practical joke you've ever played?

Released 100 crickets in coworkers work truck.
Put a heavy duty zip tie on his drive shaft and didn't trim it. It would hit the exhaust heat shield and sounded like the biggest sewing machine ever coming through the parking lot.
Poured glitter in the A/C vents and turned the air on full blast while the truck was off.

All on different occasions. He deserved it. He got me just as bad.