Gargon (Teenagers from Outer Space)

Gargons are lobster-like creatures native to the homeworld of a species of xenophobic humanoid aliens, who commonly use Gargon meat as food sources.

Biology
Gargons greatly resemble Earth lobsters, at least externally. Initially, they are the size of Earth lobsters, but if exposed to higher amounts of nitrogen or given food, they will grow exponentially, moreso if both conditions are met. Their normal full size is unknown, but on Earth, which has a higher level of nitrogen, they are able to grow larger than buildings. Although higher nitrogen levels enable them to grow, such an atmosphere would initially shock their system and make them go limp for a short period of time. With higher nitrogen alone, they can grow to a size capable of quickly tearing apart an adult Human. Gargons are entirely carnivorous, and their armored bodies can easily shrug off ballistic rounds. While alien Focused Disintegrators can easily kill them, Gargon bodies, or at least their outer armor, do not get fully vaporized by a shot.

History
At some point in the past, the native sapient species of the Gargon's homeworld figured out how to farm Gargons as a food source, although the Gargons remained dangerous. By the mid-20th century, the Gargons had become too dangerous to keep on the alien homeworld. A crew of five aliens were assigned to find a habitable planet to relocate the Gargon herds to, carrying a small Gargon aboard their ship. After finding many uninhabitable planets, the aliens came across Earth, landing on it and setting up testing equipment. One of the aliens, Thor, disintegrates a dog named Sparky upon disembarking, and another alien named Derek noticed the dog's tag, realizing Earth had sapient life. The Gargon was taken outside, surviving the atmosphere, as Derek turned on the other aliens. After Derek was restrained, the aliens noticed that the Gargon had gone limp, assuming it was killed by the higher nitrogen levels. After Derek escaped, the Gargon woke up, now thriving in the atmosphere. Two aliens, Morro and Sol, moved the Gargon to a cave, taking it out of its carrying case and holding it down with elastic restraints, as the atmosphere would cause the Gargon to quickly grow. The aliens resolved to not feed the Gargon until they returned. After reporting Earth's conditions to their homeworld, their leader personally led a fleet to Earth, carrying herds of Gargons.

Meanwhile, a series of events involving alien crewman Thor chasing Derek across a nearby Human town eventually led a Human reporter and police officer to the Gargon's cave. Entering the cave, the policeman was quickly ripped apart and consumed by the enlarged Gargon, who then grew large enough to break free of its restraints and leave the cave. Later, it attacked Derek and a Human girl named Betty, prompting Derek to fend it off with a rock and escape with Betty. The Gargon continued growing, soon towering over buildings, and marched over hills on its way to the city, sensing the large number of Humans within. Derek, hooking up power lines to a damaged alien disintegrator, managed to get enough energy into the gun to shoot the Gargon, killing it. Immediately afterwards, the alien fleet arrived, with only a guide-ship carrying the alien leader and Derek's captain landing first, the rest of the Gargon-carrying fleet remaining in orbit. Derek pretended to turn on the Humans, tricking the leader into letting him into the guide-ship, which he used to direct the entire fleet to ram into the ground, destroying the fleet, himself, the leader, and the Gargons. Gargons left on the alien homeworld are presumably still farmed, likely posing less of a threat due to the amount of them eliminated in the invasion fleet, but it is unknown if the aliens moved on to another food source or attempted the relocation process again. If they did try to relocate the Gargons again, it is very likely that they did so on an uninhabited planet, as the death of the leader presumably sparked a revolution against the leader's authoritarian regime.

Appearances

 * Teenagers from Outer Space (1959)