Hi everyone,

While dreaming I found myself doing some insight practice, investigating the three characteristics etc. when suddenly something tripped in my brain and my vision and audition started looping like a broken record. I have never had any epileptic seizures but if I had to take a guess it would feel like this. It scared the hell out of me so I quickly snapped out of this state and woke up.

I'm worried that it could cause serious brain damage if I stay in that kind of state for too long. Any thoughts?

I doubt that meditation can cause brain damage. If you are seriously concerned you can get a brain scan to check for any underlying physical problems (yes, I've resorted to that twice before!) I usually find these kind of dramatic & scary experiences purifying ... if I can stay with them despite the fear. Without knowing anything more about your practice it's hard map things precisely, but you could consider the standard sequence of a dramatic A&P experience being followed by dissolution and then knowledge of fear (& sadness & disgust, i.e. dukkha nanas). When meditators try to avoid such experiences then it's common to get stuck in some low level version of the A&P -> DN cycle ("dark night yogi") until they finally embrace them and settle into equanimity.