I've had 2 quasi-religious experiences on shrooms.
In one of them I was sitting on the kerb of a quiet street when some kids went by. Later when I looked at the kids again, down the street, I saw them vandalize some public property. These two thoughts immediately generated in my mind, very clearly, very heavy for me to accept:
1) the world is completely doomed, everybody, everywhere, forever.
2) now I know how Jesus felt on the cross (!!!).
I started crying and sobbing very bitterly. Maybe for their "sins", maybe for my own. It was a case of "my God, my God, why have you forsaken me?", not of "Father forgive them, for they do not know what they do".
The other one I was at home walking down the corridor when I passed in front of the bathroom. The door was open and I catched a glance of myself in the mirror.
For what was probably a few seconds, I saw myself as a demon in the mirror, maybe the Devil. Dark red skin, a devilish beard (I was shaven though), horns.
My hallucinations on psychs aren't very strong. They either don't occur, or they last but a few fleeting seconds, usually don't repeat, and are separated by several minutes. But the power of suggestion is immense. I was tanned, some of my hair was sticking out like horns in a few places, the shrooms and my own mind did the rest.
In case anyone thinks I'm a religious freak, I don't believe in God (the Christian one, in my case) at least since I was 13.
Think both of these stemmed from guilt. It can be a very destructive emotion. But it powers the Catholic Church or at least their sheep.