Horror films aim to scare and thrill audiences through the use of common themes including revenge, hauntings, demons and exorcism, serial killers, religious beliefs, ghosts, and graphic violence. Some examples of films that explore these themes are Scream and Halloween for serial killers; The Exorcist and The Conjuring for demons and exorcism; and Psycho for hauntings. The document discusses the themes found in horror films and provides examples of popular movies that represent different themes.