For me: LSD is like the walls of reality melting before your own eyes. Mushrooms is like you mind melted with a wild animal. DMT is like your consciousness melts with your imagination.
I agree w the above r.e. lsd/shrooms .. never done dmt tho.. not particularly interested. I've done salvia which I've been td is like a super light version of dmt, and was not a big fan.. thought at least salvia is only about 15 minutes :D lots of ominous dread.
I wonder if other people would agree with that description, but it sounds almost palpable.