South Park: Season 6, Episode 10

6 - 10: Bebe's Boobs Destroy Society

The children finally return to school for the first time after Ms. Choksondik's tragic death. Bebe has begun to develop physically since the last time they've seen her, and the boys make fools of themselves over her, without really understanding why. This makes Wendy jealous, so she sets out to do something about it.