One day, a student finds a gopher at school. He takes the animal to the custodians to be taken care of. The three men had other ideas.
The janitors decided to kill he large rodent. First, they sprayed solvent on the creature. This solvent was used to remove gum from floors and undersides of desks, so it was strong stuff. However, the poisonous spray did nothing to the gopher.
One man, being bored, lights a cigarette. At that moment, the flame from the lighter ignited the particals of solvent in the air, causing an explosion. The three custodians and sixteen students were injured in the explosion.
The gopher walked away, unscathed.