Piper Maru

List of season 3 episodes
List of The X-Files episodes

"Piper Maru" is the fifteenth episode of the third season of the science fiction television series The X-Files. It premiered on the Fox network on February 9, 1996. The episode was written by executive producer Chris Carter and Frank Spotnitz, and directed by Rob Bowman. "Piper Maru" is one of those which helped to explore the series' overarching mythology. Its introduction of the black oil became a storyline milestone for the series. The black oil would later go on to play a much larger role in the series, including playing a pivotal role in the 1998 X-Files movie. "Piper Maru" earned a Nielsen household rating of 10.6, being watched by 16.44 million people in its initial broadcast. The episode received mostly positive reviews from critics.

The show centers on FBI special agents Fox Mulder (David Duchovny) and Dana Scully (Gillian Anderson) who work on cases linked to the paranormal, called X-Files. In this episode, a French salvage ship sends a diving crew to recover a mysterious wreckage from World War II, but the crew falls prey to a bizarre illness forcing FBI special agents Fox Mulder (David Duchovny) and Dana Scully (Gillian Anderson) to investigate the source. Their investigation brings them face-to-face with Alex Krycek (Nicholas Lea).

"Piper Maru" was based around two visual images Chris Carter had wanted to include in a script "since the beginning of the show". The first of these was that of a deep-sea diver finding a still-living pilot trapped in the wreckage of a World War II-era fighter plane and the second was that of a black-and-white flashback taking place in a submarine. The title of the episode is a reference to the first and middle name of Gillian Anderson's daughter, who had been born during the production of the second season.