Shadow people are a phenomenon only talked about recently, although I'm not certain they haven't been around longer, they've only been recognized openly the past decade or so. People who witness them often describe seeing something out of the corner of their eye, turning their head and watching it disappear. Others describe a situation in which they witness more often than not a 3-4' tall dark human-shaped being that appears to be trying to be incognito. When it realizes you see it, it dashes away or disappears as if startled. They often also describe a sense of doom coming over them when they encounter one.
It's a long jump from shadowy phenomenon to evil, but you know there's going to be those with a spiritual explanation for phenomenon who are going to jump on that explanation. Why else is it black? Why else is it small and demon-like? Why else does it come with a sense of dread?
My son had an amazing experience with a shadowperson that I believe personifies the typical encounter, although this one lasted for a fair amount of time compared to usual encounters. It was a few years later when he finally confessed what happened to me and he only did that because I just explained to him why I ghost hunt because "if you had something unexplainable happen to you, you'd want answers too." His voice began to shape and he seemed visibly upset. From a highly logic-minded and gifted young adult, this was quite unusual. He proceeded to explain how he and a friend at the age of 17 snuck into a cemetery. They were walking through the grounds in the dark when they stopped about 25' away from a large altar at the outdoor crematory vaults. My son saw something very dark and dense looking next to the altar. His first thought was, a homeless person. His friend next to him said, "do you see that?" and my son nodded. They proceeded to approach the altar until they were perhaps 10-15 feet away. My son held up his digital camera, clicked on the red light that helps him to target what he wants to photograph and figured it might alert the person to leave. The red target sat atop of this dark definitely solid mass. It also frightened it and the dark mass unfolded to the same height as the altar (3' tall) and scurried behind it. My son's heart was pounding and his friend was horrified. My son rushed to the altar, beamed his flashlight on it and realized that the altar was attacked to the solid concrete wall. There was no behind to it. Feeling a heavy sense of dread and doom, they both rushed away to the side of the altar some 20 feet away and looked back. When they looked back, this 3' tall black thing peered out from behind the altar and looked at them. They ran off to the far end of the cemetery. They gave the altar wide berth and took off out the far side of the cemetery where his friend saw it move between headstones. My son shook his head as he explained it. He had absolutely no idea what it was but it was nothing he could explain. He had no belief in anything supernatural until this time and even when faced with what was happening, he tried moving around at first to see if he and his friend were casting shadows, which they couldn't since there was no back lighting. To this day, he still thinks about it and shivers.
What are shadowpeople? Well, they intrigue me because they show a sign of intelligence I've never seen in hauntings. They seem almost like what folks in Celtic cultures might have called elves or Scandanavians would call trolls. They go about their business but when they realize they've been seen, they rush off. They carry a sense of doom and dread which intrigues me. This says to me that the human being is sensing something of a living nature about this "creature." Where they show up, more often than not, is where people don't normally traffic. This makes me think they are sentient and can make the decision to go to places they aren't likely to be run into, then when they are run into--they show a startle response and flee.
The theories on shadow people including interdimensional beings that occasional blip in and out of our world, alien life forms, natural life forms we weren't aware of until we began using high frequency HD TV and computer screens that made our eyes better able to discern things we didn't have a spectrum to see before, evil spirits, and ghosts trying to manifest.
Since I have had very little experience with shadow people and both times I didn't feel a sense of dread, I can only use logic to discount some ideas. They don't seem to happen in particularly haunted places and aren't usually seen more than once in the same place, although some people claim their homes have them, they're not always seen in the same places in that home. It doesn't seem residual to me because it appears to be cognizant as well. If it's a spirit form, it's a pretty lousy one. We should have been seeing these back when folks were seeing misty apparitions and see-through ghosts and full-body apparitions, but they're a fairly new phenomenon.
I can't think of any reason we'd suddenly be getting shadow people unless they've always been there and we're just now able to see them. For that reason, my deduction so far early in my research is that, in fact, our eyes are changing to pick up things we've never seen before and because of that we're startling those beings that might have gone about their business unnoticed for so long that they took it for granted they could go anywhere and do anything. Now, they have to consider where the humans are and move accordingly. It's just a theory, but it at least holds more water than evil spirits which is folks tend to like to call anything they don't understand.
As I continue my research on the subject, I'd be excited to hear from anyone who's had this happen to them. I'm looking for common descriptions and situations that might help to explain it. I suppose the last possibility which is more rooted in the natural world is that we ourselves are projecting these things as a kind of splintering of our personality in times of stress, but I would need a lot of folks telling me they were under stress when they saw them and didn't see them when they were happy to even begin to delve into that explanation.
For now, I'll just say that our eyes are getting much better and soon we might see things in the paranormal world without the benefit of goggles and scopes. Intriguing--I can hardly wait!