Comparison with The X-FilesEpisode 7x20 (season seven, episode twenty) of 'The X-Files' was titled "Fight Club," probably a homage to dear Tyler and Co. as the episode was aired some time after the movie. The episode and the movie share no major themes, but there are a few similarities. (Note: the doppelganger factor is further discussed in the Twin Peaks comparison.)
"Fight Club" tells the story of LuLu Pfeiffer (shown above with the girls' dream man Bert) and Betty Templeton, two women who look just alike and whose lives mirror each other perfectly. When they come in contact with each other, violence breaks out around them. Mulder and Scully discover that the women are more than just twins; they are doppelgangers. As the X-Files' offical site says, "Doppelgänger (German for 'double goer') stems from German folklore, where a wraith or apparition of a living person is distinguished from a ghost. The concept of the existence of a spirit double, an exact but usually invisible replica of every man, bird, or beast is a widespread belief. To meet one's double is a sign of one's imminent death."
While Tyler is not an exact doppelganger of the Narrator, he serves the same function: he is his spiritual incarnation. Like LuLu and Betty (shown facing off at right), a wake of violence follows the pair. In the same way that Tyler and the Narrator first attracted onlookers as they fought, Betty and LuLu have their final showdown in front of throngs of people; and just as the men convinced those around them to fight, the girls made everyone from boxers to Jehovah's Witnesses turn on each other. Finally, the "sign of death" comes to pass in the movie 'Fight Club,' though in an unexpected way. One of the doppelgangers does die as a result of their meeting... it just happens to be Tyler.