Deltadust/Dustrune Idea: So for this weird take on a dumb idea, Sans, as to no one's surprise, is a murderer.]

Sans somehow gets memories from all of the bad/terrible routes from Undertale. Sans always has nightmares when he naps or sleeps, and can't really do anything about it.

and we basically know how almost all Dusttale Aus go, but he's the catch. he doesn't gain any LV or powers; he gets none of that; he's just a plain old murderer who killed his fellow monsters all over nothing, just some dreams he can't really call "real" but blames Kris for all his pain he caused in th past and wanted to stop it.