Okay, other rec. I was hesitant to rec this one because it could go either way - it's still a WIP and I've not been reading it on the lists, only on INAP (not that I'm being snobbish about my site or anything - the story started on the lists when I was away and I've not managed to catch up yet.) I Am What I Am by M McGregor. It's a very different take on the dreaded "what if Xander dressed up as something different for Hallowe'en?" stories which have flooded the 'net over the years. This is a really intriguing story which keeps getting better and better with each new chapter. Please don't let the Hallowe'en thing put you off - it's just a CPD in this story rather than the focus.