The X-Files (1993)

S4E21 Zero Sum

A postal worker is inexplicably killed by a swarm of bees in a locked restroom, prompting Assistant Director Skinner to eliminate any trace of the incident. To carry out this cover-up, he masquerades as Agent Mulder, but his ruse ultimately fails. When Mulder discovers the truth and confronts Skinner, the assistant director confesses that he is collaborating with the Cigarette-Smoking Man in hopes of securing a potential treatment for Scully's cancer.