* My child... Are you looking at something that you are not suppose to?

* This page contains content that is not safe for work or other locations with the potential for personal embarrassment, and is not safe for children to look.

* However, if you are 18 years old or older... You may find something that you like.

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Sex and mature themes (including rape and sexual assault) are included in this AU. Do not continue if you are sensitive to themes of this nature.
For a less serious NSFW AU, see Undertail and Under(her)tail.

Underlust is an AU made by NSFWShamecave, who temporarily gave permission to Skele-cakes to continue the AU. NSFWShamecave has since taken back the AU. All the characters are overly sexualized and search for sexual attention except Mettaton who was a victim of sexual assault/rape.[2] Everyone typically wears revealing clothing. Certain locations, such as Grillby's are also changed to fit the theme.


Story has been re-posted by gorillazfan666 on DeviantArt. Direct links will be provided at a later date.

Chapter 1 focuses on the relationship between Mettaton and Papyrus.

Chapter 2 introduces Frisk, and the true beginning of the story.

Original creator, NSFWShameCave, has transferred ownership of AU to the community.


  • Asriel was stillborn.