Can't remember author or name of the fic, but Spike wins the fight in Harsh Light of Day but decides that Buffy, who's hurt over Parker, is too pathetic to kill yet. So he decides to wait, which really just results in him waiting on a bench outside her dorm for her all the time, the two of them hanging out and bonding, and him subtly playing with her hair which he obsesses over. He kills Parker at one point and leaves his body outside her dorm, but does it in an attempt to be nice. A girl from the dorms, name starts with a K I think, tries to flirt with him a few times but he's obviously too distracted trying to fix and "kill" Buffy to care. Willow catches them sitting together on the bench at some point too.