Fic Rec Friday: Creature Feature

[farenmaddox]

maybe it's Sunday but who's keeping track, really?

For this week, rec your favorite fics in which Dean or Cas (or both!) is some kind of creature/monster. And for this one, Cas being an angel doesn't count - dig deeper! (Unless of course you can think of an AU where angels are something wildly different from SPN canon, then I'll allow it.)

Okay, get to reccing!