"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.