Most horror movies attempt to elicit a specific emotional response. The obvious emotions associated with horror are fear, terror and dread. Horror movies do scare people, whether that fear comes from a supernatural element in the story or knowing that what happened in the film could happen to you. Other emotional elements that come from a horror film include revulsion and a sense of helplessness. However, some movies that do not fit into the horror genre can elicit these emotions as well. For example, intense scenes in crime dramas like "The Godfather," "Goodfellas" and "Scarface" all tap into these emotions.
Not every horror movie has a monster in it, but many do, and this is at times considered its own genre. A monster can take several forms, but it almost always represents a villain for the protagonists to fight against or run from. Examples of quasi-real-life monsters include the shark in "Jaws," the snake in "Anaconda" or the crocodile in "Lake Placid." Monsters also come in the form of serial killers, like Jason Voorhees from "Friday the 13th," Michael Myers from "Halloween" or Leatherface from "The Texas Chain Saw Massacre." Sometimes the monster is a supernatural creature, like Dracula, Frankenstein's monster, the Mummy and the Wolf Man.
Depending on the film's rating, some horror movies are defined by their level of violence. The slasher genre that began with "Halloween" and was extremely popular in the 1980s relied on creative and gory killings. Sometimes horror films that carry and R rating fare better than those that carry a PG-13 rating, because horror fans expect a certain level of violence and gore. Additionally, some directors like Lucio Fulci, Mario Bava and Dario Argento pioneered entire sub-genres of horror films, in this instance the giallo horror films, which were known for their realistic violence.
Many horror movies include elements of darkness, whether it be in the plot, character or production design. The Gothic horror movies from the '30s and '40s, including Universal's original "Dracula," are known for their dark design. More recent films, like "Insidious" and the "Saw" series, have used dark design elements in their marketing, production design and special effects.
Throughout the years, new genres of horror have developed, and each one has its own core elements. Torture horror, which includes innocent people trapped in a dungeon atmosphere and tortured, was popular in the first decade of the 2000s, pioneered by films like "Hostel" and "Saw." Also in the early 2000s, several Asian horror films were remade by Hollywood. Movies like "The Ring" and "The Grudge" featured more grim elements of ghost stories and revenge. Finally, point-of-view horror movies have become popular with the availability of home video. "The Blair Witch Project" was the first major popular horror movie told in first-person with the camera. Other films that followed include "Quarantine" and the "Paranormal Activity" movies.
Not every film fits neatly into a genre, and even film experts and fans debate whether some movies are truly horror films. Additionally, some films are not marketed as horror films because filmmakers fear association with genre fiction might impact their credibility. Examples of such films include award-winning movies like "The Silence of the Lambs" and "Black Swan." Both films include many horror elements but were marketed as dramas. Other debatable films include real-crime films like "The Last House on the Left" and "Irreversible," which do not include any supernatural elements but elicit an emotional horror movie reaction from the viewer.