I have found that there are two types of dreams that these entities infuse into the mind of a sleeping person:
1. Nightmares: You see death and destruction everywhere around you. You see your loved ones die. Sometimes you see sick stuff happening to people. Like people getting dragged under a running vehicle, falling off buildings, their body parts scattered and other sick stuff. These can casue psychological damage to the victim if not physical.
2. Endless Loop Dreams: I believe that these dreams are infused to physically damage/hurt or kill a person. These dreams are not typical nightmares. These are more like endless puzzles. You find yourslef in a building and you are trying so hard to find your way out and you just go round and round, there seems no end to it. You see yourself on road and you want to reach a destination and you are trying so hard to reach it but you just keep going and going and the road never ends, sometimes you find that you came back where you started from. You see that you solve one problem in dream with so much effort and another one comes and you begin solving it and there seems no end to it. All such dreams that just go on and on and the victim is totally focussed into solving those puzzles, he is so deeply focussed into solving those puzzles or finding his way out that he never realizes that he is in a dream. He never bothers to wake up. Here only partial sleep paralysis occurs but the victim does not realize it. When he wakes up he usually feels extreme thirst and a burning sensation in the throat region. He feels exhausted. Sometimes he finds injuries on other parts of his body. Most of the times he finds a shadow person standing there. He experienced sleep paralysis but does not realize that. Now here goes my theory. I believe this is what happens here: Ordinary nightmares wake the victim up and in sleep paralysis the victim wakes up and tries to free himself. These entities do not find enough time to physically hurt a person. So they put him in solving these puzzles and then slowly and subtly begin inflicting damage to his body like inducing heat around the throat. The victim begins feeling this choking sensation or thirst or burning sensation in the dream but he is so involved into solving those puzzles that he thinks that this is happening in reality, he thinks that this is happenig out of exhaustion while finding his way out. He may try to find water in dream but does not find it anywhere and goes on searching for it. Then again comes to solving those puzzles until he is almost at the verge of succumbing to physical injuries. Its my own theory based on my own experiences and experiences of few other victims. Criticism or any other explanation is welcome.
As I said earlier, shadow people can have tangible state. They can physically touch things. So no wonder you find that your lights are switched-off. Skeptics are skeptics. Don't worry about them. Think about how you can get rid of this shadow person.