Le Horla is a short story by the French author Guy de Maupassant (1850–1893). In the first version, published in 1886, an alienist presents the story to his colleagues as a clinical case. In the longer and better known 1887 version, the tale is narrated in the first person, in the form of a diary. Its protagonist describes increasingly bizarre experiences, which he attributes to the Horla, a ghostly entity that gradually comes to dominate his life. ‘Horla’ is a neologism, believed to be an amalgam of ‘hors’ (out) and ‘là’ (there). Somatic hallucinations and an episode of sleep paralysis are followed by distressing passivity experiences, which define the story. It has been argued that the ghost in the story might represent a form of autoscopy, but the Horla is in fact invisible and the narrator experiences it as a completely alien and parasitic presence, unrelated to his own self. The Horla becomes his absolute master, in charge of his body and mind. At one point, the narrator, determined to escape the Horla's sinister control over him, and believing he is finally leaving this odious presence behind, intends to order his coach driver to take him to the railway station, but instead he asks him to take him back home, where he knows the Horla has taken residence. All his actions are now dictated by the ominous external agent:

The narrator concludes that only suicide can liberate him from the controlling ghost.

Maupassant struggled with intense psychological distress towards the end of his life, associated with his neurosyphilis. He died in 1893 in a private asylum at 42 years of age, 6 years after the publication of Le Horla. The cause of death was recorded as Paralysie Générale. He had made a suicidal attempt a year before his death. Whether or not the author's own psychiatric symptoms found their way into this tale remains speculative, but it seems likely that they at least informed (in tandem with his fondness for psychoactive substances) the description of the horrors endured by its narrator. This would make Le Horla an invaluable first-hand, detailed and vivid account of organic psychosis.