One thing that could be even scarier than a nightmare is the sleep paralysis itself. Depending on what chemicals are active at the time your body is still around REM sleep while on sleep paralysis, it could be the most horrifying (the word doesn't go far enough,) annoying, or just plain strange. During the phrase, your brain sends chemicals to your body to prevent you from doing something stupid while you are asleep (like hitting yourself or grabbing something) thereby paralyzing you. When you wake up, another chemical sets in/another part of your brains becomes active, and that chemical can be described as part of your sleep paralysis.
In my case, I only had it once that I can think of. It was to the point that my fear reached a new high. It was to the point that I felt like I might actually get hurt or be killed. Objects (clothes and shadows) in my room started turning into horrifying images. Ghastly images like the tales of aggressive ghosts haunting a home to hurt people who intrude. Instead of not being able to see them, they were there, and they were ready to get me. I can't fully describe it but menacing, terror, ghastly, and probably a whole multitude of adjectives and adverbs could be used to describe what had happened. It was just terror like there was never before. In a scale of 1-10, it would be 10 or higher. It was threatening. At the same time, I could not move, I could not talk(no yelling or screaming.) The only thing that actually moved was my eyes. It was at that time, I told myself that these images weren't real. I shut my eyes hoping that these images would disappear by the time I open my eyes again.
Has anyone actually have gone through the scenario of sleep paralysis or more than just one episode?