Okay I’m going bonkers trying to find a fic and any assistance would be greatly appreciated because I’m starting to worry it was deleted from AO3.
It’s a Good Omens x Supernatural crossover where Crowley from Good Omens is the Crowley the Winchesters know. He’s been grieving Aziraphale for a while. He’s trapped in a devil’s trap in the bunker (I think because they’re trying to make him human? Can’t remember) when the Winchesters go on a case and find this weird librarian who’s being watched by demons. They bring the librarian back to the bunker and Crowley loses his shit because it’s Aziraphale with all his memories altered.