This has nothing to do with what you described. But my one friend had told me the legend that sleep paralysis happens after youve been abducted by aliens. Obviously sounds a little crazy however I am a believer of aliens (billions of stars and planets has to be one more with intelligent life) so maybe it could be.
He told me when they abduct you, they basically freeze your muscles and erase your memory. I have once had a reaaaaal scary version of this sleep paralysis associated with abudctions (I dont claim I was abducted though lol) It was suppppeeeerrr scary. I felt paranoid something was in my room with me. My body could not move no matter how hard I tried. I was screaming in my head for my family to come and help me but my lips wouldnt move. It was like I was in acoma but was concious.
Eventually I finally did let out a yell and my body came back to its self. Thank god ive never had that agian, it was honestly the worst thing associated with nightmares/sleeping that I think could possibly happen to someone.