"Piper Maru" is episode 15 of season 3 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.