Have you ever been just sitting and minding your own business when you saw a dark shadowy movement out of the corner of your eye? It could be nothing or a phenomenon called shadow people or shadow beings. Don't know what that is? Well, the name pretty much says it all. It's a shadow in the shape of a person and some have reported they have glowing eyes, usually red. They use to be only seen out of the corner of your eye but more and more witnesses are starting to see them straight on and for long periods of time. What are they exactly? There are many theories to help answer that question.
The explanation from skeptics and mainstream science feel it is nothing but our imagination. Our minds are playing tricks on us and we are seeing things that aren't really there or there is a reasonable explanation for it. Could they be right? I think it can account for some, but can it account for all cases?
Another popular theory is that shadow people are another way of how ghost manifest, falling in the category of orbs, cold spots, etc. It's a possibility, but by most definitions of what a ghost is, it may be a phenomenon in its own category. Most entities that take form have detail to them (face, hair, and clothing) while shadow people do not. Maybe they aren't ghosts but actually demons. People who have seen them have left with dark or malevolent feelings. I think a dark figure with glowing red eyes is enough to make most people feel uneasy. But if they are demons, what is their intent with letting people see them in this manner?
Aliens are also on the suspect list. Abductions are so bizarre it's not a surprise that there is an alien theory. Some abductees have reported that the aliens grays seemed to pass through walls and closed windows and appear and disappear abruptly among other things. Is it possible they conduct their business disguised in the shadows?
So far, theories discussed in this post are ones that would probably immediately come to mind with a subject like this, but lets venture to two that you wouldn't think of unless you did your homework. With time traveling, you might think that you would just go completely from one point in time to the next. That's basically what the entertainment world has taught us. However, the idea linked with shadow people is that those from the future were able to achieve the possibility of traveling to the past but only to observe in the form of a shadow. I don't know about you, but this one seems a bit far-fetched to me.
What about visitors from other dimensions? Mainstream science think this theory is fairly possible. It's believe that other dimensions are parallel to our own but invisible. And inhabitants possibly have found a way to come in our dimension appearing only paritially visible like shadows. Psychics and sensitives believe beings on other planes exist of different "vibrations". Scientists are starting to look at reality, on a quantum level, in the same way. So, are shadow people inhabitants from a parallel dimension? Possibly.
A true explanation could be found for this phenomenon one day, but for now, it can only be observed and documented in hopes the pieces of the puzzle will once be put together.
Source: About: Paranormal Phenomena