5-methoxy-N,N-dimethyltryptamine. Fast-acting psychedelic drug similar to DMT. This substance can be found, of all places, on the backs of frogs (such as the Sonora desert toad, bufo alvarius). Note to toad-lickers: 5-MeO-DMT should be smoked as it will be broken down by enzymes in the stomach unless accompanied by a MAOI.
This comment on 5-MeO-DMT is from Shulgin's TiHKaL:
(with 15 mg, smoked) "At about 60 seconds after I smoked this free base, I beheld every thought that was going on everywhere in the universe and all possible realities while I was wracked out with this horrible ruthless love. It scared the hell out of me. When I could see again (15 minutes later) it was almost as if there was an echo of a thought in my head saying that I was given an extremely rare look at the true consciousness of it all. I've never been hit this hard since then. A definite ++++."
Watching a person tripping on 5-MeO-DMT conveyed an unprecedented feeling of intensity to me. She took the trip with expectations of a rebirth-type experience, and that's precisely what it looked like - like she was a small child again, staring wide-eyed at the world as defined by her imagination. However, 5-MeO-DMT should be considered too intense and, like the TiHKaL comment above mentions, potentially very frightening for the unprepared.