All things we call paranormal, are actually normal.
Advanced technologies and advanced personal abilities are always confusing to a human when he witnesses them, especially at first.
And when we meet alien people, the alien people are always using advanced technologies and advanced spiritual abilities to be with us and show us things.
We are also always using our own natural abilities to accurately perceive them and communicate with them.
In my understanding, what humans call "shadow people" is actually a visual affect of somebody, anybody, alive or deceased, human or another race, or other beings, that can be caused by any of a number of different factors used during the experience.