Season 1- The Jersey Devil

The Jersey Devil (episode 1x04) originally aired on October 8 , 1993 .

A homeless man is found in New Jersey woods, his body partially eaten. Agent Mulder tries to link this death to an old X-File in 1947 when a motorist was attacked, his arm partially eaten, and the police was able to shoot a half-man, half-beast creature tracked back to a cave. Mulder believes that it's the infamous Jersey Devil, a creature said to inhabit the area, and begins investigation.

Mulder meets up with Detective Thompson in the local morgue who is officially assigned to the investigation. Detective is reluctant to believe a story about the Jersey Devil. Mulder meets Peter Brullet, who found the body, as well as another homeless man who knew the victim. Both tell Mulder they believe that the Jersey Devil is behind the murders.

Agent Mulder spends a night in the street and notices what he believes might be the Jersey Devil. Mulder fails to catch the creature, but instead gets arrested by the police as a suspicious person. In jail, Mulder accuses Detective Thompson of unwillingness to investigate the case as it might disrupt the tourism industry.

Dana Scully arrives at the location to get Mulder out of jail. Agents arrive at the University of Maryland , where doctor Diamond confirms Mulder's idea that a human could return to primitive instincts of a neandertal . Mulder theorizes there might have been two such creatures, and the one he saw was female, forced into the city searching for food.

The agents, with help of the local police, attempt to track down the creature. It attacks Mulder and flees to the wood, but the police are able to kill it, despite Mulder's insistence that it should be left alive. Autopsy reveals that the female gave birth to a child recently. The child can be seen hiding in the woods as the episode ends.