Genres
Slasher
A horror subgenre, defined on film, in which a killer stalks and murders a group of people.
The slasher is a subgenre of horror defined on film: a killer or a group of killers stalking and murdering a group of people, often with bladed weapons. The formula: a past wrongful action causing trauma, reactivated by a commemoration or anniversary; a human antagonist with no moral sense (non-human killers are not traditionally counted); and the final girl, the young survivor left to face the killer at the end, though some critics argue that trope is overstated. Halloween, Friday the 13th and A Nightmare on Elm Street are the canon.
In prose and web fiction the label travels as a conventions package: episodic kills, a countdown structure and a last-standing protagonist. Unlike cosmic horror's unknowable entities, the antagonist is human, and chapter-by-chapter attrition pairs naturally with cliffhanger endings.