Along with human and extraterrestrial encounters, a global epidemic challenged Scully as she forms the puzzle pieces in "The X-Files" season 10 finale.

The final episode of "The X-Files" season 10 is entitled "My Struggle II" and it saw the revival of the franchise's larger mythology, the "walking corpse," as per Yahoo. According to the publication, the episode also featured the depopulation scheme, which was teased in the previous "The X-Files" episodes.

According to TV Line, the finale episode opened with Scully narrating her exploits, along with photos from the original series run. She tested her own DNA and got some unreliable results, with the shot changing to modern-day Scully, who transformed into an alien with a big head and shiny eyes.

Instead of ending lives on the hands of soldiers and their guns, "The X-Files" utilized viral outbreak to decrease earth's population. The viral killer had been given to the marked victims through the smallpox vaccine.

The finale also showed Scully track the cure for the disease. After linking smallpox dots, which gave deeper meaning to the contagion, Scully deduced that aliens were actually man's savior and not killer. An                extraterrestrial DNA was revealed to counter the spread of the virus and save the infected human race; this DNA is believed to be possessed by an adopted child.

The conclusion of the show's finale saw a UFO hovering over William's birth parents and it is assumed that it will bring them to a mother and child get together.