The creepy endless stairs music in Super Mario 64 was achieved using an auditory illusion called the Shepard Tone.
Part of the trick is that when the loop breaks, the higher octaves will gradually lower the volume of their notes while the lower octaves gradually become louder. Creating the illusion of a never-ending ascending pitch!
Check out this one by Velociraptori
Featured on Reddit where it got nearly 30k upvotes and 1M+ video views.
A few comments said they could clearly hear the break, I probably could have done a better job of completing the illusion. If anyone want to “remix” their own version to make it better, feel free to do it!