When I was in eighth grade I went on a trip to Washington D.C. with my school. The trip was supposed to be educational (and it was), but what I took from the trip was far more terrifying and self-aware...ing.
Disclaimer: When I say know who you're sleeping with, I don't mean having sex with. I mean of course you should DEFINITELY know that, but you should also know who you are sleeping beside.
During this trip there were four people to a room. It was myself, two of my good friends and one of their mothers. I shared a bed with the girl who's mother was not with us. One day I woke up to find our chaperone a little freaked out. She was just kind of looking at me, and when I asked her what was wrong she asked me if I remembered staring at her in the middle of the night. I replied with of course not, but she said I had to. She said it was because when she asked me what was wrong I had replied. I was a little freaked out, but after that night it didn't happen again so I forgot about it.
It wasn't until college when this started happening again...more frequently. My roommate tells me that I would often sit up in bed and just stare at her. She would ask me what was wrong and I would just continue to stare. This happened enough that we named my alter ego, and main suspect in any attempt on my roommate's life, Martha. Now, I've been lucky that every time I've traveled, and Martha has made an appearance my companions trust me enough not to believe me to be a closet homicidal maniac. I've been told that Martha can even hold small conversations.
Moral of the story: Know who you're sleeping with. In rare cases it may not be a sleeping disorder, it may in fact be a homicidal maniac. In that case....run. NOW.