"The Pine Bluff Variant" is the eighteenth episode of the fifth season of the American science fiction television series The X-Files. It was written by John Shiban and directed by Rob Bowman. The episode aired in the United States on May 3, 1998 on the Fox network. The episode is a "Monster-of-the-Week" story, a stand-alone plot which is unconnected to the series' wider mythology, or fictional history.