Sure you have… on Star Trek: TNG, when it turns out Lt Commander Remmick was a host vessel to alien invaders.                                                                                               
And we all know how that ended

Oh, don't forget Jesus turning into a thrashing Witchdoctor-y Demon as he tries to cross Antonia's barrier. What the hell was that all about?

Personally, Although a bit short, I thought Katara's challenge to the Northern Water Tribe's Waterbending Master was more artfully executed than any other battle.

@JosephS — No, last season was memorable for the fact that the best dancer, Alex Wong, was eliminated due to injury after only 3 amazing routines into the Season.

One sentence summary:
A slightly more racist version of the Antiques Roadshow…