To me, it's an AU with a premise that could have been ridiculous but was so well executed, it's not. So, good writer, good hands, good story.

That, right there, is almost exactly what I was going to say. I think "crackfic" is a term that is bandied about fairly liberally right now, but my own personal definition is exactly that: a story premise that *should* have been ridiculous (I mean, c'mon, John's a *centaur*? Give me a *break*!) but then something works so well that it becomes more than a silly premise. (and for me, I think it comes down to the characterization, mostly) (I mean, John seems so, well, *John* in that story)

And then there are the parody stories, like the one where John's an elf, Rodney's a dragon and Beckett's a, well, I forget what Beckett was, but it was really silly, yet well-written and *meant* to be silly. But I don't think that's crackfic. Like in svmadelyn's recent badfic challenge, some of that was blatant badfic parody ("It's okay, John. I know you didn't *want* to rape me. I'm just glad the unicorns are okay.")('scuse me, I'll stop ROTF any second now....) and some of it was *trying* to parody badfic and yet, twisting and sprouting into something like eliade's stories of John turning into a giant Praying Mantis, or Rodney being not quite human (but still sexy as all get out). Some people just *can't* write a bad story and that, my friend, is the path to crackfic!