Synopsis by Hal Erickson
A deadly pre-evolutionary contagion, which feeds on human body tissues, threatens the lives of commuters in the Boston subway system. Unfortunately, the local police officials insist that Scully (Gillian Anderson) and Doggett (Robert Patrick) keep mum about this threat, ostensibly to avoid widespread panic. But the two agents aren't about to allow bureaucracy or stupidity to result in catastrophe for Beantown. One of this episode's several inside jokes is the character name "Philbrick," a reference to Boston ad executive Herbert Philbrick, whose counterespionage activities in the 1950s inspired the classic TV series I Led Three Lives. "Medusa" was first broadcast on February 11, 2001.