Slender man History

Abilities

  The Slender Man's original abilities included:

selective invisibility (say, to adults or anyone without a camera)the ability to change height and body shapethe ability to shape its arms into tentaclesand/or the ability to sprout tentacle-like appendages from its back and shoulders to be used as additional arms or legs (or simply to instill fear)

Many stories seem to indicate that The Slender Man can control a person's mind, which became the basis for the Proxies in the video ARG , a trend that later spread to Slender Blogs . 

The Slender Man also originally had stronger connections to children, and many of the original stories revolved around disappearing children or featured Slender Man sightings in photos with children. 

This was often attributed to the innocence and morbid curiosity of children, which could lead them down the path of discovering the creature.

As more stories came forth, however, the use of tentacles and tentacle-like appendages became less common, and the invisibility was limited or eliminated depending on the storyteller. (On the other hand, some stories took the invisibility even further and claimed it was entirely invisible without the use of electronic devices.)

EMH, TT , ML , and DH all contain some sort of video and/or audio distortion, indicating that The Slender Man has an effect on modern digital instruments. 

This does not appear in any of the original accounts, but these also mainly make use of photographs and lower-tech video. EMH has suggested that this distortion is the effect of Sigma Radiation, a radiation said to be given off by Slender Man and the Rake. 

Sigma Radiation is also contagious, as it entered Evan's blood-stream when his arm was brutally maimed by The Rake.

EMH and ML also describe the phenomenon known as "Slender Walking".

 Slender Walking is a term created to describe Slender Man's apparent teleportation and space-time warping/teleportation between locations. 

These abilities were seen in early Slender Man accounts, and is one of the most recognizable elements of the mythos. Slender Man's ability to appear – seemingly from nowhere – in a place where he wasn't mere seconds before is one of his most terrifying traits, and EMH mentions the effect of this on a person's mental health.

Certain contemporary views see his movement as either extremely limited or impaired, as if he is incapable of moving his body properly. It is rarely seen to actually move, and goes from standing still to rapidly teleporting within the blink of an eye. 

There is no apparent coherency to his movements or position, and he is capable of teleporting several dozen times to various locations in a few seconds. He does not flee, and can be just as dangerous standing still as when obviously teleporting.

 He is capable of – and often will – stay within several dozen feet of his target, no matter how they try to escape. 

It seems to be part of his psychological attack to stay just within visual range without actually attacking – the fact that he is there, no matter what, is often described as worse than actually being attacked, the psychological effects often deteriorating the mind of the victim as a result.

He appears to be able to follow any and all targets regardless of where they go, or where and how they hide. It isn't certain how he does this, but he seems able to keep a perfect trace on its targets, often speculated to be a part of ihisspeculated existence as a potentially omnipresent being.