Fun with hallucinations

As those of you who follow along regularly will have guessed by now, I hallucinate frequently.  However, I don’t actually do a lot of drugs - this is an entirely unassisted process.  I’m talking about hypnagogic hallucinations, which most people experience from time to time when they’re not quite asleep and yet not quite awake.  They happen to me fairly often when my sleeping pattern is disturbed.  Because my natural sleep cycle is between 4am and 10am, but my desire to pay the mortgage and not starve dictates that I get up and go to work in the mornings, my sleeping pattern is disturbed every weekday.  This means I often start my day by seeing something that isn’t there.
Today’s was a real doozy.  It was a head.  Clearly not a human head, but human-like and with a large set of startlingly human teeth visible in its open mouth.  It was in many ways a reptilian looking head; the nose was essentially a snake-like snout and the ear was a vestigial hole with just a small fold of skin around it, and the skin appeared to be partially covered in pebbly scales.  I love this head!  I want to make it as a specimen for my collection.  Watch this space, and I’ll show you what I saw when I was in the process of waking up this morning.
I can only imagine how frightening this sort of thing must have been for our ancestors who didn’t understand what caused it, and it’s no surprise a lot of them thought something supernatural was going on.  Check out this article for a fascinating discussion of how people in the pre-scientific era tried to explain some of the weird things our bodies do when we sleep.  Even today, a disturbingly large number of people attribute these experiences to ghosts, demons or extraterrestrials.  It's easy to laugh at people who confuse sleep paralysis with alien abduction, but just imagine what it would be like to live in a time when the only explanation anybody had was "Aaaargh, demons!"
File:Johann Heinrich F├╝ssli - The Nightmare - WGA08332.jpg
"The Nightmare" by Henry Fuseli illustrates a common 18th century belief about sleep paralysis.