Ever get the sense that something's watching you while you're asleep? Or that there's some thing in the room? Perhaps it's under the bed or standing over you?

Perhaps it even looks something like this:

If so don't worry; you're not crazy.   What you're experiencing is what's known as Sleep Paralysis (SP).  It's when you think you're awake but you're physically unable to move.  You might also see wild, fantastical and sometimes frightning things, or feel as though something is pushing down on you.

What's really going on is that some features of REM sleep - such as full body paralysis and dreams - are intruding into Light sleep or even Wake.  However, long before EEG, humans of all cultures attributed these sensations to those of ghosts, goblins, witches, and other supernatural beings. 

Just in time for Halloween, we teamed up with dream researcher Ryan Hurd to create this inforgraphic which looks into the mythological underpinnings of Sleep Paralysis.  That alien encounter your neighbor said he had last week?  Before there were aliens, people used to report similar instances but said they were "fairy encounters." 

To look at it in all it's creepy glory, just click here.  It shouldn't be too scary...but it's okay to sleep with the light on if you need to.