Paranormal Activity is a 2007 American supernatural horror film produced, written, directed, photographed, and edited by Oren Peli.
The film follows a young couple, Katie Featherston and Micah Sloat, who are haunted by a supernatural presence inside their home. They set up a camera to document what is haunting them, using found-footage conventions that were mirrored in the later films of the series.
The film was initially developed as an independent feature and was shot for $15,000. It was then acquired by Paramount Pictures and modified, particularly with a new ending that cost an additional $200,000. The film premiered at Screamfest Horror Film Festival in North America on October 14, 2007, and was widely released in 2009. It earned nearly $108 million at the U.S. box office and a further $85 million internationally for a worldwide total of $194 million.
The film's success spawned a series of sequels and prequels, including Paranormal Activity 2, Paranormal Activity 3, Paranormal Activity 4, Paranormal Activity: The Marked Ones, and Paranormal Activity: The Ghost Dimension. The series has received mixed reviews across all films, with the first and third films receiving generally positive critical reception, and the fourth, sixth, and seventh films receiving mostly negative reviews.