I'm 25 and this has been happening to me since I was about 5. Sometimes it won't happen for a month or so and other times it is every time I try to go to sleep. If I have had a nap during the day and am not completely tired, it always happens. I have had the full out hallucinations to just getting the feeling of something very evil in the room. I have heard voices, been choked and sometimes even felt like I had come out of my body and was watching it all from a few feet in the air. At first I was able to "wake myself up" by moving a finger then a hand and by then I would be awake. Now it is much harder and I can sometimes almost vibrate my head until I wake up but can no longer move anything else. Normally I'm in bed trying to go to sleep, go to move and realise I can't, then panic sets in and horrible nightmares start, if I can't wake myself up very soon then the nightmares turn into horific hallucinations. Like the person who commented above, most nights I don't go to sleep until after midnight and leave the tv on. If anyone knows some way to prevent or stop this please let me know.