"Fight Club"

The agents cross paths with a pair of doppelgangers whose close proximity leaves a trail of destruction.

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. In Irish and northern English folklore, it is known as a "fetch." A fetch can be seen usually only by persons with second sight, and is most commonly seen by a special friend or near relative just before or at the moment of death of the original.

Mirrors have their own superstitions. Primitive peoples believed that when a man saw his own image in a pool or any other reflecting surface, what he saw was not a mere reflection, but his soul looking back at him. The notion that the soul could be separated from the body without causing death, and that it was sometimes visible as a reflection or a shadow, existed all over the world in early times, and appears in many well-known folk tales.

LuLu Pfeiffer is named after LuLu Powers, a regular catering chef for Ten Thirteen Productions.

The wrestling scene was filmed at the Grand Olympic Auditorium in Los Angeles. An open casting call was put out for extras to appear in the stands to see the bout between Randall "Tex" Cobb and Rob "The Van Daminator" Van Dam. The venue was built for the 1932 Olympic Games and was the largest venue in the U.S. at the time. Throughout the 1930 s, 1940 s and 1950 s it was home to some of the biggest boxing, wrestling and roller derby events.

Koko's Print Shop was actually just an empty warehouse. The art department filled it to look like a working copy store.