Have you heard of "Brain Flossing" or "brain massaging"?
It's taking over TikTok as a way to soothe & destress by using "8D" audio. according to a NYPost article, it's a "a supersonic illusion that causes each ear to hear tones at different frequencies." This noise is supposed to have a soothing effect, as if your brain is getting a massage.
Check it out: