Yea I experience that rarely atleast once to twice a year, I describe what it's like ,you go sleep of a night and when wake up ,your immediately fully awake in your mind ,you try so hard to open your eyelids to see but in those minutes your mind won't help you to remember how to open your eyes, you panic in your mind but its not just the eyes but the mouth ,unable to speak ,unable to remember how to open your mouth and move all your limbs but your awake in your mind fully conscious and experiencing all that for minutes then seem like ages and ages ,the experience is absolutely terrorfiying as I should know.