 Trepkos tells Mulder that after Firewalker returned from its first descent, Erickson pulverized a rock in one of its samples, resulting in his death and the infection of all the scientists immediately surrounding him.Trepkos says that the organism is parasitic in nature, making its hosts pass itself on to others.Meanwhile, in the lab, an infected O'Neil handcuffs herself to Scully to expose her to the fungus, forcing Scully to use a hammer to split the chains but to no avail.