Sleep Paralysis
So there is a phenomenon that sounds like some weird Grimm tale and utterly ridiculous unless you happen to experience it, in which case you may try your hardest to forget. I am not working on my fiction writing- I am just talking about sleep paralysis. I have heard some friends jokingly call it their sleep paralysis demon, because it's like your dreams project themselves into your awake life for a couple of minutes until the brain wakes all the way up and the brain system that keeps you paralyzed, so you don't act out your dreams, turns off. The demon idea comes in because during those truly terrible 60-120 seconds your sleep brain has free reign and for some of us tends to project the feeling and visuals of a malevolent presence beside you. Just think of it like if Pokemon Go hated you and was made of your nightmares (no big right?). A lazy internet search suggests that around 20% of the population has this, and I have been told it can be made worse by stress and bad sleep...