Ok, so I am totally freaked out now...
I did research on this Slender Man figure. Supposedly he is a made up boogie man like figure meant for teens and college students. He was created in some message board called Something Awful, and a few internet groups have taken in this mythos and expanded upon it.
This made me feel a little comfortable for a bit. Maybe I had just read something about this Slender Man a while back and it subconsciously came back to haunt me?
That was, until I read another message.
"The Slender Man has not always been known by that name. A group of creative teenagers and college students on Something Awful may have given it a name and expanded on the figure with their fictional stories, but, history has always had figures like this 'Slender Man'. In medieval Germany, there was a tale of a tall, slender nobelman dressed in fine black silk robes that would silently stalk the forests at night. In the day, he paraded as a figure of nobelity, but at night, he would cast off his borrowed face and hunt for his prey - mostly children who had sinned.
In the colonial times, a tale came up in many settlements of a man with spider like limbs that lashed like whips. This man was tall, slender, and hid among the trees, stalking and killing the settlers who strayed too far at night. He was claimed to have no face, and dressed in fine black formal wear.
In modern times, the Slender Man is seen in a black business suit and appears to be faceless. Witnesses claim he does not initially show his various limbs, until he is ready to kill.
In various accounts through out all the recorded stories, the Slender Man seems to have the same traits. He is very tall and slender (hence the name.), he wears black clothing that fits the era, he has a hypnotic effect on children and some times teens - forcing them to come to him, let him inside their homes, and other actions they would not do in their normal state of mind. He seems to be able to stretch and his limbs and grow new ones, to help catch his prey, or to help hide. Some accounts claim that the people involved thought he was nothing but tree branches, only to have been caught by surprise. The Slender Man seems to also enjoy instilling fear and panic in his victims and will often stalk them for days or weeks. It is theorized that he feeds off of these emotions. Modern accounts claim that his presence effects electrical impulses and often causes magnetic interferences with electronics. He also supposedly does not show up in night vision or thermal vision, as claimed by a US marine (who was soon discharged on the basis of insanity soon after giving his report.)"
This made me feel as if my heart dropped in to my stomach...Another person agreed with that message, saying that the posters on Something Awful may have had repressed memories, and that something triggered them to remember. Another said that children are more intuned with their senses and may have actually seen this Slender Man at one point or another. He or she (I couldn't tell by the username. It was a band name.) claimed that for a month, their little brother was telling his mother that the 'Tall Man came to visit' in the night, and couldn't sleep because it scared him.