Jeff the Killer is a story accompanied by an image of the character. The story says that a teenager named Jeff was going to a friend's birthday party with his younger brother when they were attacked by a group of bullies, but Jeff manages to defend himself and hurts the bullies badly leaving them lying on the street beaten up and with their arms and hands broken. After this incident, Jeff realized he enjoyed it and liked to harm people, went insane, and the next night he cut off a part of his face in the shape of a smile, as well as his eyelids so that he will never sleep. After that he murdered his parents and brother (to the latter he whispered "Go to sleep" while murdering him) and now he is a serial killer who sneaks into houses at night and whispers "go to sleep" before murdering his victims.

The Slender Man (also known as Slenderman) is a fictional supernatural character that originated as a creepypasta Internet memecreated by Something Awful forums user Eric Knudsen (also known as "Victor Surge") in 2009.It is depicted as a thin, unnaturally tall man with a featureless head and face and wearing a black suit.