oho, this resembles my few experiences with mushrooms (mixed them with lemon juice for shorter but much stronger experience) - I laid down on the bed, relaxing music in the background, and gradually lost all the senses. I mean all of them - even sensing your own body.
I didn't have hands, eyes, or anything physical - I became (i think white) mist of atoms, whirling in an endless dance (think mist in the hamam and when you blow air through it).
It didn't happen suddenly, but very gradually. When it began to (very slowly) fade, I slowly recombined from those atoms back into my personality, started to rediscover physical parts of existence - breath, eyes, hands etc. I could still perfectly recall what was happening with me 1 hour ago (unlike say alcohol which just dumbs you down to potato), but mind was less and less able to comprehend the whole picture with all the subleties - it literally shrank back. After main trip was gone, I still had 1-2 hours of literally walking down the hill with intense emotions of absolutely pure happiness and inner peace. Very spiritual, especially for an atheist/agnostic person like me.
Massive mental exhaustion afterwards with very strong headache, but that was the price I was willing to pay.
By far the strongest experiences in my whole life (and i've been through some stuff), absolutely positive without a single negative atom. The beauty of psychedelics is they work with who we are inside, and thus it's a very unique experience for each of us, not much transferable/understandable beyond vague descriptions.
But that breakdown and reassembly - I literally had the feeling that if I had some mental issues, they would definitely manifest right there. If you come from bad background, have some issues, do evil stuff without reason etc don't do them, the risks are then too big and those forces are titanic