The Thing in the Backrooms by ThatExoGuy
Channel: Fear Forge
Date: 16/12/2021

Yeah, you can unwillingly cross into another, vaguely hostile dimension not hospitable to human life, and that's bad. But it gets worse.
Story found on Reddit NoSleep: https://www.reddit.com/r/nosleep/comments/mhf9he/the_thing_in_the_backrooms/

Music:
Kevin MacLeod: Lightless Dawn, Shadowlands 1-7, Classic Horror 1-3, Anguish, Trepidation, Quinn's Song: First Night and A New Man
https://www.youtube.com/c/kmmusic/featured