I've had a few experiences of sleep paralysis in my life. They occurred on the transition from sleeping to waking.
The first time was when I was a young teenager. I had an experience that lasted for an atypically long time (a few minutes), where I could not move at all, and saw out of the corner of my eye a dark figure hovering over me and I couldn't do anything about it. I couldn't scream, I couldn't move any part of my body from my head all the way down to my toes even the tiniest bit, so I was in a state of silent unmoving panic, basically. For a few years after that I believed that ghosts most likely exist because I had not ever heard of sleep paralysis and had no other better explanation for it.
The next time was when I was in college, and I couldn't move for a while and there was a figure over me. But this time, I identified it as a state of sleep paralysis so I just calmly waited until I could move again. I used that time to basically just observe the experience because it was novel.
The third time was a couple months ago where I couldn't move and someone was over me, holding me down. Rather than assume a supernatural event, my initial panicked impression was that it was a home intruder and I was being raped. I tried to fight back but couldn't move. Within a few seconds when the paralysis subsided, I sat up and screamed and then immediately realized I'm fine and it was sleep paralysis. It was a pretty frustrating few seconds because I kept thinking like, "I could totally take this guy but I can't move!" and then when it was over I was like "oh. -_-'"