Alien Slug (Alien Opponent)

This unnamed slug-like species are used by an unnamed humanoid species as living booby traps.

Biology
Members of this species begin life as palm-sized, flat, brown slugs with no visible sensory organs, moving with an inching fashion. While bearing no visible teeth, they are capable of burrowing into Human bodies, and consume the blood of living beings. They are born in swarms within large, soft eggs resembling several green and white balls put together, filled with a green slime substance. Additionally, once inside the body of a larger being, they are able to metamorphosize into considerably larger chestburster-like forms. However, this has only been seen happening within the chest cavity of Human females, and very little of the larger form of the alien slug was seen by Humans, so any abilities it may have, as well as its full body shape, are unknown. Unlike the sapient aliens that use them as traps, these slugs are capable of surviving in Earth's atmosphere.

Behavior
Alien slugs actively seek out prey, even beings far larger than themselves, and move in swarms. They only attack living prey, as many were seen passing over a corpse without burrowing into it.

History
At some point in time, an unnamed humanoid non-oxygen breathing species learned how to use eggs of this species for living booby traps. Due to the slugs being able to survive in an oxygen-rich atmosphere, it is likely they are not native to the aliens' homeworld. In 2010, an alien ship carrying at least one of these eggs crashed on Earth, where the alien pilot placed one of these eggs as a trap to keep Humans out of the perimeter. When dozens of dimwitted trigger-happy Humans entered the junkyard, seeking the corpse of a murdered man left near the crash site for a $100,000 reward, one of them shot the egg, releasing all of its slugs. One of the slugs jumped on a Human and quickly burrowed into him, killing him as the other slugs swarmed a nearby group of Humans. One of the Humans, a soldier, threw off a slug that had gotten onto a grenade he carried, although the action also pulled the grenade pin. The soldier was then distracted by seeing a female member of his group, who he just realized could've been his long-lost daughter, allowing the grenade to explode, destroying him and all the slugs still on his boots. At least two slugs then burrowed into the body of the woman the soldier had been looking at, and while one slug was cut out by her companions, another metamorphized and burst out of her body, before it was killed by a gun-toting priest. The first slug was kept in a jar by the Human that removed it. The slugs continued to roam the area until one of the Humans welded together a flamethrower and metal armor, burning away the slugs, except for the one kept in the jar. After a few days, the slug's new owner used it to kill a sleazy bounty hunter in her way by throwing the slug at him, letting it burrow into him and burst out of his face. It is unknown what became of this slug afterwards, or if any others were still aboard the alien's ship when it left Earth.

Appearances

 * Alien Opponent (2010)