South Park: Season 8, Episode 1 - ProjectFreeTV

8 - 1: Good Times with Weapons

The boys buy ninja weapons, and when they won't allow Butters to play with them, he re-emerges as his alter-ego, Professor Chaos. Of course, an anime-style battle ensues, and soon Butters gets a ninja star in the eye. The boys must figure out how to remove it without getting in even more trouble.