Jeff the Killer

Jeff the Killer arose within collaborative online horror writing and role-play. According to sourced accounts, the character concept was created in October 2008 by a user named "Sesseur," and later that month a user named "killerjeff" expanded the lore while role-playing and posting stories on sites such as Newgrounds. Multiple circulated origin variants exist within the fandom: common versions depict Jeff as an adolescent who, after violent confrontations with bullies and a disfiguring incident (rendered variously as burns, acid, or other injury in different tellings), descends into homicidal behavior. Another prominent variant emphasizes that Jeff becomes murderous after being shunned and judged as a potential killer on account of his disfigurement. These narratives are part of a mutable, community-authored set of stories rather than a single canonical myth.

The character is strongly associated with a widely circulated, heavily edited image of a pale, scarred face with an exaggerated smile; the exact origins of that image are uncertain. Sources note a "touched-up" version used in early postings and community attempts to locate an "OG photo" have been reported, with the image serving as the central visual marker for the character across fan works. Beyond the image, textual descriptions in stories typically portray Jeff as a young male who is physically disfigured in the course of his origin narrative.

Sources present Jeff the Killer primarily as a human turned violent rather than a supernatural being. In the dominant narrative he is described as a teenager who goes insane and embarks on a killing spree after traumatic events; he is popularly represented whispering the phrase "go to sleep" before killing victims. Fan works and role-play sometimes expand or vary his capacities, but the sourced material does not document canonical supernatural powers or cosmological abilities beyond extreme violence, intimidation, and the narrative catchphrase.