Class of Nuke 'Em High (1986)

An accident at a nuclear plant causes a radioactive water leak which ends up gruesomely killing a student at a nearby school after the tainted water reaches the drinking fountain and a gang of students turn into violent psychopaths by the runoff from the plant. Leaves from a radioactive marijuana plant located in the yard of the nuclear plant are smoked by a couple and the mutated drug shows itself to have potent aphrodisiac effects, leading the couple to have sex n later the girl immediately becomes pregnant and spits a little monster into a nearby toilet. The creature travels through the water pipes and lands in a barrel filled with radioactive waste, and mutates into a bigger creature causing mayhem in the school.