South Park S01 E05 An Elephant Makes Love to a Pig

"Four boys. One f**ked-up town."

Stan notices a new addition in their bus stop crew, an elephant standing alongside Kyle. At school, class lessons for the day involve genetic engineering (conveniently enough). Kyle questions the possibility of a genetically engineered elephant made smaller by design. The boys have to beat the rough kids in their genetics experiment, and will try anything to do it.