Jeff the Killer itself? No, and if it were, it certainly wouldn’t be so unknown, after all, how would it be possible to ignore a murderer leaving a trail of blood behind and that no one can capture?
However, here we enter the darkest part of the question, although he himself does not exist, it is not impossible that people similar to him exist, mainly in the mental aspect.
A mental trait of Jeff is that he suffers from severe Mental Insanity, but what exactly does “Insanity” mean in this specific context? My guess is that it would be a mix of Borderline, Sociopathy, Severe Chronic Insomnia, Pseudobulbar Affect, Central Nervous System Depression and Frototemporal Dementia. Let’s see each one of them.
Borderline Personality Disorder is an ongoing pattern characterized by emotional unstability, strong emotions, fear of abandomment, unstable relationships, distorted self-image and tendency to suffer from mood disorders and pathological feelings of guilt. This part is what makes Jeff the Killer very complex mentally, because in the midst of that increasingly serious insanity that will one day kill him (you’ll understand this later on), Jeff is a scared and helpless child who doesn’t want to be left alone, only since no one wants to be around him because of his appearance he expresses his anger and frustration through his sociopathic side.
I think it’s precisely Jeff’s borderline essence that shows that there is still some humanity there, including a little-known story where he visits the grave of his dead family and demonstrates guilt and genuine grief. However, his insanity quickly get the control and he sets out to kill yet another wretch.
Sociopathy, known officially as Antisocial Personality Disorder (ASPD), is an ongoing pattern characterized by disregard for social norms, disregard for the safety of self and others, lack of empathy, lack of remorse, manipulative behavior, and inability to control anger and impulses. We already had signs of this before the accident that disfigured him, in one version, he violently beats up bullies to defend his brother and felt no guilt about it afterwards.
Insomnia is a chronic sleep disorder characterized by difficulty maintaining a healthy sleep routine and falling asleep, it usually varies in intensity over time, although the tendency is to get worse if not treated. Jeff burning his eyelids was probably a symbology for him to have developed insomnia, and as he didn’t seek treatment, it got worse and started to affect his already damaged sanity. Note: I really don’t think it could be literal, as if the eyelids were removed or permanently damaged, the hypothetical person’s eyes would dry out and she would be permanently blind, which would make it difficult for her to murder and evade authorities.
Pseudobulbar Affect is a neurological disorder that causes the patient to experience hysterical and uncontrollable laughter during stressful/traumatic situations. I don’t think I need to say, his first reaction when he caught fire and when he saw his disfigured face was a hysterical laugh that even he wasn’t able to control.
Central Nervous System Depression is a disorder that causes the brain and body to have difficulty communicating properly, causing low blood pressure, difficulty breathing, paleness, slurred speech, mental confusion, disinhibition, amnesia, psychosis, and if not treated, it can lead to coma and even death. We see some of these traits in him, most notably pallor, mental confusion, disinhibition and amnesia. Some versions of the story say that he often spends a considerable period of time doing nothing, I can conjecture that it is the coma generated by the occasional worsening of this disease, that’s because the symptoms vary over time.
Frototemporal Dementia is a type of dementia characterized by the destruction and progressive atrophy of the Temporal Lobe. Emotional symptoms include mood swings, which the patient may not be aware of, including inattentiveness, aggressive behavior toward self or others and distorted judgment. Language symptoms include loss of speech, inability to read or write, loss of vocabulary, and general degeneration of motor skills. Jeff currently demonstrates moderate parts of both groups.
You see, a person with these disorders could become a Jeff the Killer, or at least something close to it. But we must remember that, having these disorders, it doesn’t matter if the hypothetical person escapes from the police forever or is arrested forever, eventually he will be fated to die and “retire”, because at some point the Frototemporal Dementia will have worsened so much to the point of him not being able to even do simple everyday things, which will eventually lead to his death (that is if the disorder in the central nervous system does not get worse and ends up killing him instead of just causing a coma).