I've had insane trips on psychedelics, not disassociatives where I've seen insane stuff. But the one thing most of those included was sleep deprivation. If you stay up for more than 24 hours and trip, it will be insane. The worst was having stayed awake on a binge of coke, meth, heroin, ecstasy and weed.. on the 3rd night awake my friend and I took one ecstasy pill each. We ended up seeing mailboxes turn into people harvesting carrots, we saw Jesus born in the sky, cartoon rabbits were dancing around, the bike path i was walking on fell apart under my feet and shattered into puzzle pieces, trees became demons, the tops of trees were dragon heads fighting each other.. etc. etc. The scariest part was after I had fallen asleep for the first time in 3 days.. had gotten about 15 minutes in and then got arrested as the cops came to serve a warrant on the guy's house I was at then I got picked up as a fugitive of the law. The part where I get arrested as a fugitive of the was not part of the hallucinations either... that was VERY real. You can imagine how much the come down sucked, heh.
Anyways, off single substances I've also seen incredibally off the wall stuff. DOB is the king. The DOB experience is exactly like the bullshit stories you hear acid trips described as by school teachers.
There was another time I took shrooms and small grassy hills became cartoonish furry dinosaurs. I saw time open up and drip from the sky. All this was while driving on I-495 right outside of DC. I was doing like 40 mph most of the way back to my girlfriends house. I have no idea why those shrooms were so good.. I had split an 8th with my girlfriend, meaning 1/2 an 8th each and we both got the same results. The shrooms were picked in a field in Florida a week earlier.
Then a 10mg dose of 2C-T-2.. snorted. I've never had such intense synesthesia. The strange thing was that I was thinking remarkably clear during the experience which lasted 8 hours, but the audio and visual hallucinations were out of this world. After an hour into it, I put on some headphones, put in a Thee-O's Alien Abduction tape and closed my eyes. The next thing I know is that I not only can see the music, but I end up getting sucked into my headphones and the music is actually a universe of color and patterns and I'm nothing but a bodiless conscious without form.
I've got tons of crazy stories, but right now not enough time or motivation to post them all or go into great detail. For a few years I wanted to be a psychedelic guru on top of my other failed dream to become a rockstar. One day I'll write a book about my better drug stories and hopefully people will read it so I didn't put my brain through all of that for nothing.
Oh, and for you people who believe that you can attain some super enlightment from insanely intense psychedelic experiences like what I've described.. sure, you can get enlightenment.. but it's worthless. The rest of the world doesn't care. There's nothing you can do with it. You're better off getting a good job and buying a house and finding happiness in a soulmate. That's where the real enlightenment is at.