Horror films seek to elicit a negative emotional reaction from viewers by playing on the audience's most primal fears. They often feature scenes that startle the viewer through the means of macabre and the supernatural, thus frequently overlapping with the fantasy and science fiction genres. Horrors also frequently overlap with the thriller genre.
The term "horror movie" first appears in the writings of critics and film industry commentators in response to the release of Universal'sDracula (1931) and Frankenstein (1931), but has since been applied in retrospect to similar films from the late 19th and early 20th centuries. Horror films deal with the viewer's nightmares, hidden worst fears, revulsions and terror of the unknown. Although a good deal of it is about the supernatural, if some films contain a plot about morbidity, serial killers, a disease/virus outbreak and surrealism, they may be termed "horror".
Plots written within the horror genre often involve the intrusion of an evil force, event, or personage, commonly of supernatural origin, into the everyday world. Themes or elements often prevalent in typical horror films include ghosts, torture, gore, werewolves, ancient curses,satanism, demons, vicious animals, vampires, cannibals, haunted houses, zombies and serial killers. Conversely, stories of the supernatural are not necessarily always a horror movie as well.
Early horror movies are largely based on classic literature of the gothic/horror genre, such as Dracula, Frankenstein, The Phantom of the Opera, and Dr. Jekyll and Mr. Hyde. More recent horror films continue to exploit the monsters of literature.