Mark Johnson was presumably a member of the Millennium Group and a practitioner of necromancy. He was able to summon four corpses in preparation for his vision of the impending end times on the eve of the year 2000. Mulder and Scully were called in to investigate the ritualistic nature of a grave exhumation that led them to meeting with Frank Black. Black's insight led the agents directly to Johnson's rural Maryland home, where he had a hobby of taxidermy and where the four summoned beings were kept in his basement. While investigating the house, Mulder was locked in the basement with the zombie-like creatures, but he protected himself within a circle of salt on the ground. Black realized that Mulder would not be able to handle Johnson himself, so he went to help. Johnson believed that Black was availing himself to be a fourth such being after Mulder shot one in the head, effectively re-killing it. Black had no such intention and tied up Johnson. Along with Scully, he was able to save Mulder and destroy the remaining zombies. Johnson was then taken into custody.