Here is an interesting one. This excerpt is taken from www.kindofcrap.com :
I haven't told many people this, but I actually suffer from something of a sleep disorder. It's not something that happens a whole lot, but before I knew what was causing it, it's something that would scare the living shit out of me a little bit more each time it happened. Y'see, occasionally, I'll wake up and find myself unable to move. That may not sound too frightening by itself, but believe me, waking up and realizing you are unable to move any part of your body is not the most comforting way for consciousness to first greet you. Usually it takes up to 30 seconds for it to fully sink in that no matter how hard I try, I simply cannot even wiggle a finger. After that, I'll try calling for help, and soon enough, screaming for anyone who could possibly hear me, before I even realize no sound is coming out of my mouth, because I can't move my lips. Then the shortness of breath kicks in, as I start thinking that, if the rest of my body won't move, maybe my lungs can't either. It will feel as if some unknown force is smothering me, exerting some kind of heavy pressure right on my chest. And so I'll be laying there, maybe about a minute in to all of this, completely paralyzed and practically wanting to cry because I'm wondering if I'm about to die. But this isn't even the bad part.
No, see, that comes when the hallucinations start.
Thankfully, as I read further, the same excerpt provides further explanation:
I typed "sleep paralysis" and "can't move wake up" into Google, and within seconds I had dozens of sites detailing this phenomenon. Which leads me to wonder: Man, is there anything Google CAN'T do?
So, as I found out, what basically happens during these little fits is that I wake up while my body is still in the REM sleep cycle, which is when we dream, and, incidentally, when our non-essential motor functions are turned off so we don't act out our dreams in our sleep. So all that happens is I wake up too early, while my body is still paralyzed and my brain is still in the 'dream zone'. Thus, I AM actually awake, but then as I begin panicking because I can't move, the dreams my mind is still having begin tailoring themselves to my panic to try to rationalize what is going on. I've read on sites that what the paralyzed person sees completely depends on that person's personality, on what he fears or uses to justify the unexplained. Some people see large individuals holding them down physically. Some actually believe there is an elephant sitting on their chest. Me, I see ghosts and demons. What does that tell you? I see too many f*cking movies.
Anyway, this disorder apparently is fairly common, and caused mostly by irregular sleep schedules. After reading that, I realized that pretty much every time it happened, I had gone to sleep at a time very different from my usual bedtime, like just for a nap or going to bed way too early. After reading that, I finally felt reassured, and now, even when it happens, I can usually will myself into moving a finger (or, as the case may be, wiggle my big toe), and from there move on to the rest of my body, fairly calmly since I now know what's causing it when I wake up like that. It's still not fun, per se, but now it's just a minor annoyance more than anything else. I do try to avoid naps though, because it's funny, it happens almost half the time I take one.
So I'm not the only one insane here! Actually I experienced those things too. I freaked out, naturally. And knowing the facts behind it, I've stopped freaking out since it's just another scientific phenomenon. And guess what, when I got back to Jakarta and got to enjoy a blissful, (almost) stress-free and rather boring life, with more than enough sleeping time, I never experience this anymore!
Anyway, this reminds me of the happenings a few years ago on a family outing in Mount Bromo (it's a mountain in East Java area), where we stayed in a hotel. A rather creepy hotel. Anyway mountainous areas sometime have their own collection of ghosts. Of course, having a lot of kids in our group and being rather cheapskate, just like every other Indonesian, we rented 3 rooms for our whole group and covered every inch of the available space in each room for sleeping. What happened is that 3 persons sleeping nearest to the windows of 3 consecutive rooms, all had sleep paralysis at the same time. Now, coincidence or not, that was creepy.