Crackfic

Some crackfic scenarios include characters transforming into animals, swapping bodies, swapping gender, swapping consciousnesses with inanimate objects, becoming inanimate objects, de-aging rapidly (from twenty-six to six in the space of seconds), and traveling through time (to name just a small handful).

I have to disagree with you here, however; the content of the episode in question is the sort of thing I'd expect to find in a crackfic - written because it's too insane an idea to just be left alone, enjoyable in its own way but not remotely on the level of something actually *intended* to be good - and it isn't improved significantly IMO by having been animated.

[…] and what a tragedy it was that I'd never finish my epic, multi-fandom, crossover crackfic saga (though there were not, in my opinion, nearly enough comments expressing this latter regret).