TheBackRoomsRebod

On May 12, 2019, an anonymous user started a thread on /x/, 4chan's paranormal-themed board, asking users to "post disquieting images that just feel 'off'", accompanying the thread with the photograph.^[

Another user replied to this post, giving the image its name and supplying the first description of the Backrooms:

If you're not careful and you noclip out of reality in the wrong areas, you'll end up in the Backrooms, where it's nothing but the stink of old moist carpet, the madness of mono-yellow, the endless background noise of fluorescent lights at maximum hum-buzz, and approximately six hundred million square miles of randomly segmented empty rooms to be trapped in
God save you if you hear something wandering around nearby, because it sure as hell has heard you