Stop it Slender is a co-op competitive gamemode for Garry's Mod based on the indie video games, Slender and Slender: The Arrival. The gamemode was released on Aug 22, 2013 in the Steam Workshop for Garry's Mod.
As a human, players work together to be the first one to collect all eight pages scattered throughout the map and avoid getting caught by the Slender Man.
The player is armed with only a flashlight and a photo camera. The battery gauge on the top left cornet of the HUD is the player's danger meter, which reduces if the player is close to being caught by the Slender Man. It will reduce if the player looks directly at Slender Man or if it is next to the player. If the meter is empty, the player is caught and eliminated from the game. The meter can recover up to 40% if the player is not losing any battery power after a short while.
The Slender Man has the ability to catch players if they look directly at Slender Man or by standing next to them. Their body colors, seen by the Slender Man, determines how close the player is being caught. Once their body turns completely red, they are caught and eliminated from the game. Slender Man also has the ability to become invisible. While invisible, Slender Man can move fast but will not catch players if they stare at Slender Man while invisible. When Slender Man is visible, Slender Man will be able to catch players if they look at them, but Slender Man will stand still if they do. However, Slender Man will move at a very slow pace while visible. Also, Slender Man cannot become visible if he is within the human's field of vision while invisible. The goal of Slender Man is to catch all the players and prevent any of them from collecting all eight pages. If at least one of the humans collect all eight pages, Slender Man will be eliminated.