I have had what you might consider "blackout" experiences on high doses of psilocybin. That is, in the 5+ gram range. What generally happens is, I might be accepting the very intense come up, with all the eye-watering and weird body load, getting a bit anxious, then settling in. I might put my headphones on, start to experience very intense psychedelia, and before I know it, an hour or two might go by where I KNOW I listened to something, but cannot identify it. There is often and very, very strange serious of events that play out that are very loosely related to the music, but are also very much psychedelic and VERY bizarre. It is almost DMT like, where you experience ego death without even being consciously aware of it, losing the fear of losing control, and just kind of disappear. It can be alarming, and sometimes I have a very hard time recalling exactly what happened and how much time elapses. I actually have come to know and expect this experience when taking what might be considered heroic doses of mushrooms. And yes...it is like blacking out, but realizing it after you "return", only to finish the rest of the trip out and eventually come down. In some ways, I prefer this total and complete ego-loss and detachment from reality to the effects of other psychedelics such as LSD and what not, and again, liken it to, in some ways, a breakthrough DMT experience where you feel transported to another dimension, or another reality. It's scary sometimes, but blissful once you accept it.