Slender Man is a creature or
being with various nebulously defined characteristics and abilities.
Slender Man was first mentioned in Something Awful Forum's "Create
Paranormal Images". Slender Man generally appears (in modern times) as a
tall man in a black or grey suit, red or black tie, and white shirt,
with no eyes, mouth, or clearly defined facial features. It has no hair,
and generally has normal-looking bare hands. Slenderman typically is
depicted in imagery and literature as between 6 and 15 feet tall,
depending on the situation, and in video as around 6-7 feet tall.
Because of its inexact nature, and differences between series, no one
has yet determined what it is.
Currently, the two leading theories as to what the Slenderman may be are the Tulpa Effect and Quantum Theory.
The internet popularity of Slenderman has spawned a massive amount of
interconnected ARGs, collectively known as the Slenderman Mythos.