Lot of LSPIQ in this thread. Paralysis during sleep is what you are describing that everyone has. When people refer to Sleep Paralysis as a sleeping disorder, they're often describing a situation where your conscious mind awakens while you are still asleep. You're body is still asleep, unable to move, (which is a normal function while you are sleeping to keep you from running out in traffic at night) but your mind is awake (when this happens, the paralysis is supposed to stop). Dreaming actually rarely occurs during an episode of sleep paralysis, because like someone mentioned above, It happens in REM sleep while your brain activity is much lower, suggesting little dreaming. When I have it, My conscious mind remembers what my subconscious mind is doing during REM. It's really more comparable to a screen saver than a dream. I see floating objects, Spiders, and black shadowy figures in my room. Show me a person that says they've been abducted by aliens or sees ghost and I'll show you a person suffering from sleep paralysis disorder.
Sleep walking is a related disorder, where your mind stays in it's subconscious state, but the switch in your brain controlling the paralysis is set to the awake mode allowing you to move about. I've never sleep walked, but I hallucinate while in bed often.