Slender Man (Movie based on true story)

The Slender Man is an alleged paranormal figure purported to have been in existence for centuries, covering a large geographic area. Believers in the Slender Man tie his appearances in with many other legends around the world, including; Fear Dubh (or, The Dark Man) in Scotland, the Dutch Takkenmann (Branch Man), and the German legend of Der Großmann or Der Grosse Mann (the Tall Man).

The Slender Man is a being (male in appearance) who looks like a man with extremely long, slender arms and legs. He also appears to have 4 to 8 long, black tentacles that protrude from his back, though different photographs and enthusiasts disagree on this fact, and therefore it is theorized he can 'contract' these tentacles at will.

He is described as wearing a black suit strikingly similar to the visage of the notorious Men In Black, and as the name suggests, appears very thin and able to stretch his limbs and torso to inhuman lengths in order to induce fear and ensnare his prey. Once his arms are outstretched, his victims are put into something of a hypnotized state, where they are utterly helpless to stop themselves from walking into them.
The Slender Man by Pirate Cashoo

He is also able to create tendrils from his fingers and back that he uses to walk on in a similar fashion to Doctor Octopus. The superhuman stretching ability could also be seen as a similarity between himself and Mr. Fantastic.