The alien species consists of five forms from infancy to fully grown.
Stage One: Alien Egg.
Alien eggs are extremely sensitive to their surroundings. Any species approaching them might trigger their hatching, or worse, a Facehugger attack.
Stage Two: Facehugger.
Once the alien egg begins to hatch, the Facehugger produced has two purposes: survival and finding a host. Facehuggers are small and move quickly with incredible leg strength. Once it finds a host, it pounces on their face, pries open their mouth, and injects the alien embryo through their throat into their body. At this point, the Facehugger supplies oxygen to preserve the host's life. Once the embryo is injected, the Facehugger's mission is complete, and they die automatically.
Stage Three: Alien Embryo.
Injected from the host's mouth by the Facehugger, it is the fetal stage of the alien, parasitizing the host, absorbing host DNA to modify and perfect itself, and altering the host's DNA to sustain the host's life.
