Totally random bit of information, that always boggled me.
In high school, I was a total, drug abusing nut. LSD, Shrooms, coke, reefer(still lol) alcohol, opium, and pain pills...lots. I have had so many bizare occurences on these things...Anyway to get to the point. The only hallucinogen I was terrified to try after hearing what it dad was Dramamean. (Spelling). It's sold in stores, at your local wal green and such as something to help you sleep, I believe. A lot of my friends abused this...and all of them had the same reports. After ingesting it, a friend of theirs, or celebrity, or something would appear infront of them. They all said it seemed real. As real as could be. They would sit and have hour long conversation with this friend, and suddenly in the blink of an eye they'd be gone. Even after doing this, they'd take it again and have the EXACT same experience and EVERYTIME truly believe whoever it was was right their, hanging out...It wasn't until the next day, sobered up that they could realize how nutty what they were saying was.
I even knew someone who went to re-hab because he woke up his family and neighbors screaming out his window telling his friend "Go home! It's to late! I can't hang out!!!!"
No one was there.