[Lawtan]

Ehh...Slenderman would be one of the most successful modern internet urban legends, with the Slenderman Game mechanics being a new door to horror games (collect x notes with a monster chasing you, teleporting or getting faster as you collect them, and if you stare at him, you start either seeing jumpscares or static with loud noise. Stare too long = dead. Caught = dead)

Slenderman is something that can be scary, or can be cute. There is a "fake documentary" thing researching Slendy by the Marble Hornets...

Essentially: Tentacles + Teleporting + Faceless + MIB (the suit) + Alternate dimension stuff...