False Memories AU/FicRecs
From Transcendence AU Wiki
Untitled by avafalls (mod A) (link)
What about heartwrenching headcanon? What if Dipper actually died during the Transcendence, but Bill got weakened a lot and was imbued with Dipper's memories, feelings and will to the point he actually thinks he's him...until, years later, he finds Dipper's reincarnation.
Pseudomnesia by Greyingdawns (link)
Alcor wakes one day to find himself back in the Mystery Shack as if the Transcendence (and all that followed) never happened.
Resurrection by Doceo_Percepto (link)
When Ford claims that Bill Cipher can be banished permanently, Dipper is ready to get rid of the demon for good. Too bad neither of them anticipated the consequences.
