I've had them when I was in my last really bad mixed state. I think it was from sleep deprivation. I was awake for 5 days straight. had visual hallucination like you described and auditory hallucinations when there was white noise around me, I heard voices in it talking to me. but again I think it was more from the lack of sleep. but that was caused by the mania. so idk. but yes, I've experienced what you described before.