I welded a wrench to the table. Left the handle sticking out off the edge of the table. My shop teacher came along, mad as we always left tools out, and grabbed the handle. His reaction was priceless.
The wood shop got these super small dowels, so I cut off a piece and painted it at home with model paint - shiny metal model paint. My friend tried to weld something with it - when it burst into flames - it was hilarious.
We did stuff like that all the time. Loved shop class in school. Well, not quite all the time. Once in auto shop, my bud left the oil filler cap for a car sitting on the rad. He started the car, the cap fell into the fan and got shot out right through the rad. The same dolt hooked a boost up battery to battery, not using a ground, and the being-boosted battery exploded.