Sleep Paralysis is a phenomenon in which people, either falling asleep or waking up, temporarily experience the inability to move. Scientifically its the transition state between wakefulness and rest characterized by complete muscle atonia (muscle weakness).
I’ve known several people who have had sleep paralysis, who have even made characters who share the same trait. I’ve never suffered from it myself but I find the folklore around it fascinating, because no matter what nation of origin it always has to do with the visitation of a demon or vengeful spirit who either sits on, restrains, or strangles said victim. And so I drew my own little depiction of it, complete with a demon girl puking black stuff on a guy.
I dunno, sue me.