It's the dead of night; you are fast asleep. Suddenly, you are wide awake, but unable to move. Hunched over you in the shadows is an eight - or nine - foot tall gaunt entity with spider-thin limbs, dressed in an old-style black suit, its pale face missing eyes, nose, ears and mouth. You finally manage to cry out. The monstrous thing disappears as suddenly as it appeared. You just had a terrifying encounter with the Slenderman. Who - or what - is the Slenderman? His existence began on the Internet, but he didn't stay online. The Slenderman may be a tulpa, a thought-form that can stride out of our darkest imaginations and into reality if enough people believe in it. In May 2014, two young Milwaukee girls almost killed a friend in the name of the Slenderman. Perhaps, like the vast Skynet system in the Terminator movies, the Internet is turning against us - and attacking us with digital equivalents of our own online nightmares. The Slenderman has come to life. For the first time, this book reveals the full and fear-filled saga, including: Why just being near him can result in the "e;Slenderman sickness"e; - anything from nosebleeds to paranoia to nightmares. How one attempted murder in the Slenderman's name set off a chain reaction of violent acts, including many suicide attempts. Why he prefers approaching children in forested areas (though he has been "e;seen"e; by teens and adults in a wide variety of locations).