In this AU Sans decided to study humans and asked Alphys to create pills, that will turn him into a human. But because of her obsession with anime, Alphys accidentally has created pills that not only turn monsters into humans but also into women.
Sans - has transformed into a breastless woman with medium length hair. He has the same attire as regular Sans, except a hat with Sans' face and a red earring on her right ear. His eyes have a white sclera, but when using magic, they turn black with blue irises.
Papyrus - the first to eat pills, he has transformed into a big-busted woman with short hair. He has the same attire as regular Papyrus, except shades and red earring on left ear.
A lot of other characters has received their transformations, including Gaster, Asgore, Alphys, Undyne, Shyren, Napstablook, Nice Cream Guy, Burgerpants, Grillby and Flowey, but for the lack of their importance, they weren't included.
On March 20th the doujinshi based on Underlilytale AU was released. It was sold on COMIC CITY 22 convention for 500 yen. It has 52 pages.