Its funny, Dusttale and Disbelief aren't actually AU's they are timelines. They have the same time, same characters and same behaviors, but just different things that happen.. In disbelief, Sans tries to kill the human when papyrus was supposed to capture them leaving papyrus to fight the human at the last corridor and in dusttale sans remembers all the 364 timelines that happened and tries to grind XP to kill the player.. also Last Breath is a timeline as well