Paranormal Activity is a 2007 American supernatural horror film produced, written, directed, photographed, and edited by Oren Peli.

It is often cited as the most profitable film ever made, based on proportionate return on investment, although such figures are difficult to verify independently[8] as this is likely to exclude marketing costs.

Katie claims an evil presence has been haunting her since she was a child, so Micah sets up a camera in their bedroom to record any paranormal activity that occurs while they sleep.

Psychic Dr. Fredrichs visits the couple and suggests Katie is being haunted by a demon that feeds off of negative energy and is intent on tormenting her.

When the couple leaves the house, the camera records an unseen force moving the board's pointer on its surface, which then spontaneously catches fire.

The couple finds non-human footsteps on baby powder Micah sprinkled in the hallway; its path leads to a burnt photograph of a young Katie in the attic, thought to have been destroyed in a house fire.

After a moment of silence, Micah's body is violently hurled at the camera which is knocked off the tripod, revealing Katie standing in the doorway with blood on her shirt.

Attempting to focus on believability rather than action and gore, Peli chose to shoot the picture with a home video camera.

[13] In casting the movie, Peli auditioned "a few hundred people" before finally meeting Katie Featherston and Micah Sloat.

"[13] During a guest appearance on The Jay Leno Show on November 3, 2009, Sloat and Featherston explained they each saw the casting call on LACasting.

The film was shot out of sequence due to Peli's self-imposed seven-day shooting schedule,[14] though he would have preferred the story to have unfolded for the actors as he had envisioned it.

"It was a very intense week", Peli said, stating that the film would be shot day and night, edited at the same time, and would have the visual effects applied to it as the acting footage was being finalized.

The DVD also impressed DreamWorks executives Adam Goodman, Stacey Snider, and finally Steven Spielberg, who cut a deal with Blum and Peli.

[14] DreamWorks' plan was to remake the film with a bigger budget and with Peli directing, and only to include the original version as an extra when the DVD was eventually released.

[14] Blum and Peli agreed, but stipulated a test screening of the original film before going ahead with the remake, believing it would be well received by a theatrical audience.

[14] During the screening, people began walking out; Goodman thought the film was bombing, until he learned that the viewers were actually leaving because they were so frightened.

[20] The version with the new ending made after Paramount acquired the film was screened on September 25, 2009, in twelve college towns across the United States; the venues included Boulder, Colorado; Columbus, Ohio; Madison, Wisconsin; and Seattle, Washington.

A day later, Paramount announced that the film would have a full limited release in 40 markets, playing at all hours (including after-midnight showings).

[35] Additionally, at the end of the film, 15 minutes worth of names were added to the DVD release, as part of a special promotion.

It had more success when it opened to 33 theaters on October 1, 2009, doubling the box-office reception, grossing $532,242 for an average of $16,129 per venue, bringing the 10-day total to $776,763.

The website's critical consensus reads, "Using its low-budget effects and mockumentary method to great result, Paranormal Activity turns a simple haunted house story into 90 minutes of relentless suspense.

[39][40] Ebert stated in his review, "It illustrates one of my favorite points, that silence and waiting can be more entertaining than frantic fast-cutting and berserk f/x.

Michael Carter of The Breeze summed up the film as "all right", though denouncing its reliance on "cheap jump scares and an even cheaper 'found footage' style".

"[44] Marc Savlov of The Austin Chronicle called it "an excruciatingly tedious YouTube gag cleverly marketed to go viral".

[47] The monetary success of Paranormal Activity compared to its budget made it the most profitable film of all time, surpassing The Blair Witch Project (1999).

[48][49][50] It directly led to found footage becoming a horror movie trend for years, with The Last Exorcism, Apollo 18, The Devil Inside, and the V/H/S series arriving in its wake.

[57] A video game called Paranormal Activity: The Lost Soul was released by VRWerx for the Oculus Rift, HTC Vive and PlayStation 4.