Paranormal Activity is a 2007 American horror film written, co-produced, photographed, edited, and directed by Oren Peli. It is the first (chronologically, the third) entry into the Paranormal Activity film series. The film centers on a young couple, Katie and Micah, who are haunted by a supernatural presence in their home. It is presented in the style of "found footage", from cameras set up by the couple in an attempt to document what is haunting them.
Originally developed as an independent feature and given film festival screenings in 2007, the film was acquired by Paramount Pictures and modified, particularly with a new ending. It was given a limited U.S. release on September 25, 2009, and then a nationwide release on October 16, 2009. The film earned nearly $108 million at the U.S. box office and a further $85 million internationally for a worldwide total of $193 million. Paramount/DreamWorks acquired the U.S. rights for $350,000. It is the most profitable film ever made, based on return on investment, although such figures are difficult to verify independently as this is likely to exclude marketing costs.
A parallel sequel, Paranormal Activity 2, was released on October 22, 2010. The success of the first two films would spawn additional films in the series: the prequel Paranormal Activity 3, released on October 21, 2011, and sequel to the second installment, Paranormal Activity 4, released on October 19, 2012, a spin-off titled Paranormal Activity: The Marked Ones released on January 3, 2014 and Paranormal Activity: The Ghost Dimension released on October 23, 2015.