I'm looking for a Spuffy fic where instead of Dawn magically being inserted into everyone's lives and memories, the monks instead give Buffy the Key in the form of her getting pregnant.
It turns out Spike is the father, though I can't remember if their sleeping together was a fake memory or real. Buffy is at the hospital with Willow and Spike and Xander walks in and hears that Spike is the father. He runs to Giles at the magic shop, wanting to transmute the Key into some other form to 'save' Buffy from having to bear the baby of the undead vampire. They start looking for the spell while Buffy and Spike hurry to the shop to stop them. However, they decide not to go through with it. I can't remember the title or author or where I read it, but I want to read it again!