DMT, or dimethyltryptamine, is a powerful hallucinogenic that can be found in living matter, including the human pineal gland. Small quantities of DMT are released during REM sleep. In 1990, Dr. Rick Strassman received FDA approval for a clinical study, the results of which can be read in Strassman's book "DMT: The Spirit Molecule". Users commonly reported being transported to "another dimension" and had contact with "insect-like alien beings". The late Terence McKenna was particularly interested in the drug, and coined the term "Machine Elves" in reference to these contacts. If reading isn't your thing, listen to comedian Joe Rogan's energized thoughts on the matter. (embedded video).