I remember this from the 90's. Brain machine. https://en.m.wikipedia.org/wiki/Mind_machine

I thought I was going to get a seizure tbh. Do not recommend.

I had one of these and used it a lot in 8th and 9th grade. Then in the fall of 10th grade, I woke up one morning with the left side of my body numb and ended up having 6 grand mal seizures in the afternoon. The doctors never figured out why and they haven't come back but my mom forbid me from it after that. I do wonder if anyone else experienced that.