The nature of the alien species is explored to a slightly greater extent in the second film. A professor claims that they originated in the Large Magellanic Cloud (also called the Magellanic Galaxy), due to it apparently being the only other place carbon-based life forms have been discovered. It is also stipulated that they were a "cancerous" race that visited Mars millions of years ago and annihilated all life on its surface (which is described in the film as being Earth-like at that time) before leaving a remnant of their own DNA in its soil. This DNA was intended to be picked up by other visitors so that their species could continue to infect other inhabited planets.