Continuation of the Black Oil's Development

In Season 5, the Black Oil seems to act as a hybrid between the Black Oil of Season 3 and Season 4. In Patient X, Krycek infects a young boy with the Black Oil in order to prevent him from The boy's eyes, nose, and mouth become inflamed, similar to human responses to the green blood of the Alien Bounty Hunter and the alien-human hybrid clones. He does not initially seem infected, unlike season 4 portrayals in which the infected person merely becomes incapacitated. Here the oil body jumps to Marita Covarrubias. Covarrubias then becomes a test subject for the Syndicate, who are attempting to develop a vaccine against the black oil/alien virus. The virus will be used to infect mass populations through the use of bees and genetically modified corn grown for pollen. In the X-Files feature film, two new developments emerge: it becomes clear that the Black Oil had been present on the earth at the time of cavemen, and existed as the blood of an organism that also inhabited the planet at that time. It also becomes clear that the virus has mutated in the present time, causing a new organism to gestate in the host it inhabits, consuming the host and then birthing itself from the host's chest. These changes leave the black oil as an almost entirely different entity than it appears as in "Piper Maru." Over the course of two seasons, the Black Oil shifts significantly, using humans as transportation, then as sustenance, and finally as a means of creating a new being that entirely supplants the host.