South Park: Season 9, Episode 11

9 - 11: Ginger Kids

Cartman gives an oral report on "Ginger Kids" - kids with red hair, fair skin, and freckles - and convinces the other students to shun them. Due to a little prank, Cartman himself becomes infected with "Gingervitus" and, upset by all the teasing he originally promoted, he convinces ginger kids to follow his lead and fight for "Red Power."