South Park (1997)

S1E5 An Elephant Makes Love to a Pig

Stan spots a surprising new member of their bus stop group: an elephant next to Kyle. During school, the day's lessons focus on genetic engineering, which feels oddly timely. Kyle wonders if it's feasible to create a smaller elephant through genetic modification. Determined to outsmart the tough kids in their genetics project, the boys are willing to try anything to gain the upper hand.