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1. Ménage à trois by Beewritesstuff (Mimispace)

   Fandoms: Undertale (Video Game)  

   • Explicit
   • Creator Chose Not To Use Archive Warnings
   • Multi
   • Work in Progress

   17 Dec 2025

   Tags

   • Creator Chose Not To Use Archive Warnings
   • W. D. Gaster/Sans
   • Sans (Undertale)/Reader
   • W. D. Gaster/Reader
   • W. D. Gaster/Sans/Reader
   • Sans (Undertale)
   • W. D. Gaster
   • Toriel (Undertale)
   • Alphys (Undertale)
   • Asriel Dreemurr
   • OT3
   • Polyamory
   • Angst and Fluff and Smut
   • W. D. Gaster Is Not Related to Papyrus and Sans
   • Alternate Universe - Everyone Lives/Nobody Dies
   • Scientist W. D. Gaster
   • Scientist Sans (Undertale)
   • Gaster and Sans are together
   • But maybe there's room for one more
   • soft affection
   • in time anyway- Gaster is a raging prick at first
   • Undertale Monsters on the Surface
   • Post-Barrier Breaks (Undertale)
   • Alternate Universe - Canon Divergence
   • Alternate Universe- Gaster never 'fell'
   • Hurt/Comfort
   • Stalking
   • Not from the two fine Monster gentlemen though

   Summary

   Ten years post-barrier, and the first Ebott Tech Expo is being held right in the city- hopefully, a project that will grow and flourish for years to come.

   If only Sans could get Gaster to stop instigating fights with the woman who ran the convention center.

   Language:

   English

   Words:

   58,101

   Chapters:

   7/8

   Comments:

   51

   Kudos:

   173

   Bookmarks:

   46

   Hits:

   3,785