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1. Dynamical Change by Nightmares_Midnight

   Fandoms: Undertale (Video Game)  

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

   17 Jan 2026

   Tags

   • Creator Chose Not To Use Archive Warnings
   • Dreamtale Nightmare Sans (Undertale)
   • Underlust Sans (Undertale)
   • Bad Sanses | Nightmare's Gang (Undertale)
   • Polyamorous Bad Sanses | Nightmare's Gang (Undertale)
   • Alpha/Beta/Omega Dynamics
   • How Do I Tag
   • Mating Cycles/In Heat
   • Undertale Skeletons in Heat
   • Underlust Alphys (Undertale)
   • Sub Dreamtale Nightmare Sans (Undertale)
   • Caring Dreamtale Nightmare Sans (Undertale)
   • Eventual Smut
   • Killer Sans (Undertale)
   • Horrortale Sans (Undertale)
   • Dusttale Sans (Undertale)
   • Xtale Sans | Cross (Undertale)
   • Error Sans (Undertale)
   • Omega nightmare sans
   • Pack Dynamics
   • Nightmare accidentally pack bonds with the lust brothers
   • Dreamtale Nightmare Sans Needs a Hug (Undertale)
   • Slow To Update
   • Not Beta Read
   • We die like Nightmares mental health

   Summary

   It's a fairly normal multiverse, however, Lust AUs seem to have figured out a way to combat their endless heat. The cure? Giving everyone a specified 'classification'. That being Alphas, Betas, and Omegas.

   One day though, Nightmare finds himself in one of these universes after a bad fight with his brother. What will happen when he's been injected with their 'cure'?

   Series

   • Part 1 of Omega Nightmare Fics because I'm obsessed
   • Part 1 of Dynamical Change; The Series and Extras

   Language:

   English

   Words:

   14,773

   Chapters:

   8/25

   Comments:

   54

   Kudos:

   141

   Bookmarks:

   22

   Hits:

   1,787