This page gives a detailed list of all of the traits and abilities shown by the Slender Man.
One of Slender man's most infamous of abilities, Slender Walking, is an ability of the Slender Man that allows him to appear and disappear at will, granting him his omnipresent-like movement, allowing him to teleport from one point to another virtually anywhere instantly and often without any physical indication of the teleportation.
The ability is often explained in a variety of forms, and depending on the depiction in that medium, it may be substantially different (i.e., a paranormal explanation rather than a scientific one, or a demonic explanation rather than an alien one, etc.). The theory of Slender Man as a Fourth Dimensional Being is one of a few explanations to try and explain this using the Quantum Theory, but to date, no factual statement has been made that fully determines this explanation.
The most supported theory is that the Slender Man takes the appearance of a member of higher class, rank, or notable social position (a knight, a warrior, or a suited man), in order to gain trust or acceptance from a person, or at the very least to blend in at a distance. This was based on evidence drawn from a 16th century woodcut entitled "Der Ritter," which depicted a knight with elongated limbs believed to be Slender Man. While the image has been proven fake, the folklore of similar beings around the world in different attire still support the theory. A variation of this theory is that Slender Man's appearance varies from person to person slightly, appearing how the individual's mind comprehends it.
It also should be noted that in the early mythos, Slender Man appeared to have a face, but it did not appear on film. This seems to suggest that he can make himself appear to have a face, but that this illusion, while visible to the human eye, does not transfer to film. This is a possible ability he could use to blend in, as a faceless person would stand out a bit and onlookers would start panicking, allowing his target to escape in the ensuing chaos. This is similar to the faceless Noppera-bō, who would "wipe away" their face to terrify their victims, except Slender Man wants the opposite effect by concealing his face.
In some pictures of Slender Man in a forest, he can easily blend in with the trees in the background, sometimes using his tentacles like branches.
The loose definition of "Mind Control" is utilized and assured by many series across the mythos and perpetuated in blogs and video series. Exactly what this mind control entails is extremely loose and very poorly defined, although it is always an inevitable topic when discussing Proxies, a term coined by DarkHarvest00.
As most series state, proxies work on behalf of Slender Man, who controls their thoughts and feelings, and through that, their actions. Proxies may still have partial free will, and may or may not know that they are being controlled. They are used to interact with other victims, set traps, or give information to the victims on behalf of Slender Man. It is debated as to the full independence of proxies, and some suggest that when under his control, proxies act as a collective hive-mind. Examples include the Collective of TribeTwelve. It is assumed in some iterations of Slender Man that he is capable of puppeteering and controlling the proxies directly; however, such evidence has never actually been shown in a Vlog or Blog, only assumed.
Early Slenderman blogs attributed his mind control to a substance known as Azoth , which would come out of injured proxies.
It is important to note that Proxies are not used in the series MarbleHornets, and the major antagonist is The Operator, thus this section has no correlation with that series.
In Slender Rising 2, the player can find a shotgun to defend themselves from the Slender Man in an otherwise lethal situation. If the player has the shotgun equipped and Slender Man isn't around, the player may suddenly find themselves aiming the gun at their head at random, with static appearing in a similar manner to the moments where the player sees Slender Man. If the player doesn't break free, the player will shoot themselves.
Rarely seen in the contemporary mythos, early mythos accounts show Slender Man's ability to impersonate or mimic the voice and tone of a person, in order to get to a victim. The most common use is voice mimicking, for the purpose of luring a child or victim out of a safe area. He is also able to produce the sound of a child's giggle, perhaps to draw another child in.
Tentacles/TendrilsTribeTwelve, the tentacles played prominent roles in the Original Mythos. Slender Man's tentacles number into the tens regularly, and it is unknown how many he can spawn, usually from his back or shoulders, though he most commonly spawns about six. The tentacles themselves are used primarily for reaching, grabbing, or overtaking obstacles, and have been shown to be rather powerful. Some Original Mythos stories and images make use of Slender Man's tentacles for balance, walking/supporting, or climbing, not dissimilar to a spider's legs. This is one of the only other ways Slender Man has ever been shown to move besides Slenderwalking.
During Chapter 5 of Slender: The Arrival this is one of the ways he will capture Lauren on her way to the Radio Tower, by actually spreading out his tendrils throughout the forest in attempt to block any means of escape.
It should be noted depictions of his limbs vary in size, shape, and flexibility. Some artists even portray his limbs as having hands attached to them.
For more information see: Distortion
One of the enduring traits of the Slender Man is selective visibility. The Slender Man potentially has the ability to choose who sees him and when, in many cases. For instance, he can allow only one person to see him, or only the prey, but not anyone else who would be looking at the same place. Often, young children can see it when adults can not, and it is commonly agreed that even when humans can not detect it, he can be seen by cameras, both digital and pre-digital, although there is often distortion when captured digitally.
The only problem with selective visibility is that it makes it nearly impossible to discern who has actually seen Slender Man, and who might be making up tales for attention. While this ability is generally regarded as factual, it has not yet been proven true and the chances of selective visibility ever being proven true are very slim.
Some suggest that animals are receptive to the Slender Man, and that the Slender Man's selective visibility is not effective towards them, and it therefore kills animals that pose a threat to its hunt. This could be an explanation for the appearance of bags filled with animal corpses in early mythos.
In MarbleHornets, The Operator shows the ability to appear and disappear at random, however it's not made clear if he can be seen sometimes only with the camera, sometimes both with and without the camera, and sometimes only when not using a camera. The movie "Always Watching " indicates The Operator can only be seen truly when on camera. How much The Operator's behavior connects to Slender Man's behavior seems to be entirely based on interpretation.
Early mythos and some ARGs have strong connections between Slender Man and fire. In the Original Mythos, almost all Slender Man visitations are accompanied by fire, either after or during. He may be able to use pyrokinesis, which is the ability to move or control fire with one's mind. Often, the fire kills witnesses, or destroys evidence of its existence. Photography of the fires often show the Slender Man in or around the fire.
In some cases, the fire is blue and on rare occasions green. It is not known why this change in color occurs or what motive any of the fire has, although chemicals are known to change the color of fire.
Slender Man possibly posseses the ability to move objects with his mind, it appears to have done so in Episode 6 - Healthy Eating of EverymanHYBRID and also in Chapter 6 - Escape of Slender: The Arrival where doors close by themselves.
A common early trait of the Slender Man was that of body mutilation. A common procedure would be the discovery of a missing person's body impaled on a tree limb, high above the forest floor. Medical evidence would suggest that the person was often alive during the impalement; however, bodily sensation would likely have ceased quickly from blood loss depending on the impalement location. This was often accompanied by the removal of organs, which were then placed into plastic-like bags or sacks of unknown origin, and then replaced back into their original positions in the body. This was usually seemingly done while the victim was alive; however, removal and physical contact with organs would most likely have sent the victim into shock or killed them in seconds, rendering a fast death.
Also, alongside the desecration of victim's bodies was the mutilation or death of animals, usually cats or small animals, but occasionally dogs, for reasons unknown. Often, mutilated animals would be left in plastic sacks or bags, similar to the organs of victims, in the forest or around victim's homes or where they would find them.
Exactly how he was able to cut open a person or animal's body is unknown, but it may have likely been the use of his bare hands; his fingers are often long and bony with a sharp looking tip, it is possible that the tips of his fingers were sharp enough to make incisions into soft flesh.
Virokinesis "The Sickness"
Main page: The Sickness
In several series and ARE, characters in contact with or in some form of relationship with the Slender Man may come under sickness. The sickness causes coughing, bleeding from the mouth, nose, or eyes, vomiting, disorientation, potential black outs, and potentially fevers which first appeared in TribeTwelve and can now be seen in MarbleHornets and MLAndersen0. In EverymanHYBRID, the sickness is attributed to Sigma Radiation, which is assumed is released by the Slender Man. This may make it a form of radiation poisoning.
It is important to note that outside of ARE's and ARG's, very little data exists on how the sickness works.
In many of the Slender Man games, the Slender Man often stalks the players in weather or day conditions that cause fear, such as the night, fog, rain, or storm. Also, in Slender, fog grows thicker when the player collects more pages, thus making it more possible that the Slender Man has some degree of control over the weather.
In the beginning of Slender: The Arrival, as Lauren gets closer to Kate's house, the time of day seems to rapidly go darker, eventually turning to night as the player arrives at the house, this may indicate that Slender Man not only is able to control the weather, but is also able to accelerate the day and night cycle to a selected time of day.
Slender Man's presence causes several negative effects on the minds of his victims including inhibiting memory loss while also adding memory, altering sense and perception of a person's environment, influencing a person's personality in a very negative way such as causing a great deal of paranoia, nightmares, and hallucinations etc. it is believed that the presence of Slender Man directly causes negative effects on the minds of whom it manifests to. there is evidence that supports this belief. People who encounter The Slender Man constantly become extremely paranoid of his next return, easily irritated or agitated, severely depressed, and sometimes even suicidal this method of negatively changing a person's personality could most likely be a result of his mind control. This could also be a result of the "Slender Sickness" and his mind control as the sickness majorly factors into these symptoms but Slender Man's method of controlling one's mental health is still unexplained.
Pain Reduction/Prolonging Death
It is believed that Slender Man can reduce the pain in a human. In the CANYOUSEEMYWORDS entry JOHNNY BOY. Johnny mentions that it was because of Slender Man that he was still alive and to type despite Habit's torture. Johnny mentions that his stare is soothing like morphine.
Despite lacking facial features, Slender Man can sense when his victims are near at all times. This can be noted in both Slender and Slender: The Arrival, as he never hesitates and always has sight of the player (even when off-screen). This ability has been given the nickname "Slender Sense" by the fans.