This video was published back in April 2013 and Internet users are still arguing whether this is fake or real captured incident from a surveillance camera. The phenomenon was filmed CCTV cameras in an unidentified residential building. CCTV camera fixed a dark figure, perhaps a ghost or a demon, who attacked a man in the corridor, says the author of the video on YouTube 
A photo from open sources “Ghost” knocks a person down and a couple seconds dragging a leg along the corridor. Then he lets go and disappears. Reality or a well-posed trick? Anyway, It is alleged that there were other complaints from tenants and visitors, who were afraid of such meetings.
The shadow man, also known as the “shadow image”, “shadow creature “or” dark mass “is alleged paranormal entity. Paranormal Researcher Heidi Hollis expressed the belief that Shadow People are malicious supernatural personalities.
Some scientific points may be used to explanations of this phenomenon. This is mainly about finding causes of “shadow people” in optical illusions or hallucinations under exposure to drugs or other physiological effects on the body.
For example, when stimulating the left temporal-parietal region of the brain, similar illusions may arise. Also, these episodes may be caused by pareidolia in the peripheral sections of vision, which may be explained by the fact that the brain often misinterprets unfamiliar objects of shadow / random flashes of light as defined outlines. The phenomenon of “Ghosts” in science is also often associated with pareidolia.
A photo from open sources
Especially often the phenomenon of shadow people is associated with hypnogy (eng.) – a physical state when consciousness man is between sleep and wakefulness. During this state, the person is conscious, but the brain can “raise” images from the subconscious, similar to sleep.
A similar linking of Hypnogogia and Shadow People was made because many people who had this condition later reported some “moving shadows” and “living rays of light.” In the West Hypnogy even unofficially got the name “Face phenomenon in darkness, “just for such hallucinations.
