I sometimes suffer from episodes of sleep paralysis. The symptoms don't always include paralysis (at least for me) and can just be "dreams," really hallucinations, outside of REM sleep. The scary thing is that sometimes I don't realize that I have even fallen asleep before the hallucinations start.
One school night a few years ago, I was watching TV in my bed and I felt myself lift out of my body. I found myself staring down and watching myself looking at the TV. I lifted to the top of the ceiling slowly, still looking down at my body as I rose. As this took place, I felt a negative and dark energy surround me. I did not feel alone and whatever the energy or entity was, it was all around me. Then, as I expected it to happen, I was thrust back into my body and was completely alert and awake.