"The Erlenmeyer Flask" is the 24th episode and the first season finale of the science fiction television series The X-Files. Written by executive producer Chris Carter, and directed by R. W. Goodwin, the episode continues with the mythology story arc which started with "Pilot". The episode first aired in the United States on May 13, 1994 on the Fox network. With 8.3 million households turning in during its initial broadcast, the episode was the most-viewed episode of the show's first season.