what is improbable from the x-files?
It is the thirteenth episode of the ninth season of the series "The X-Files".
Improbable (The X-Files)
"Improbable" is the thirteenth episode of the ninth season and the 195th episode overall of the science fiction television series "The X-Files". 
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Improbable (The X-Files) [SEP] Introduction
"Improbable" is the thirteenth episode of the ninth season and the 195th episode overall of the science fiction television series "The X-Files". The episode first aired in the United States and Canada on April 7, 2002, on Fox, and subsequently aired in the United Kingdom. It was written and directed by series creator and executive producer Chris Carter. The episode is a "monster-of-the-week" episode, a stand-alone plot which is unconnected to the mythology, or overarching fictional history, of "The X-Files". The episode earned a Nielsen rating of 5.1 and was viewed by 9.1 million viewers. The episode received mostly positive reviews from critics.