Psychlo

The Psychlos are a race of hairy, 9 foot tall, 1,000 pound, sociopathic humanoids. Their homeplanet, Psychlo has an atmosphere very different from that of the Earth, and their "breathe-gas" actually explodes upon contact with even a trace amount of radioactive metals, including uranium.

Background History
The Psychlo discovered evidence of mankind's existence upon accidentally coming across the Pioneer 10. They located the plaque, which was made out of gold-anodized aluminum, a very valuable substance on the galactic commodity market. Because of this fact, the Psychlo used it to guide them to Earth around the year, where they invaded and ultimately enslaved the entire human population around the year 2,000AD to work as gold miners and to "keep them out of the way" of the Psychlo plan of operation.

This enslavement lasted for a millennium, during which time Earth became a backwater world even for the Psychlos, and assignment to it was considered similar to an assignment to Hell. Around this time, an incompetent and equally greedy Psychlo named Terl was assigned to Earth, and has his term extended indefinitely. Fearful of the simple idea of spending his years on Earth, he decides to buy his way of the planet while at the same time become ridiculously wealthy. He discovers a large vein of gold in the Rocky Mountains, but cannot go near it himself as it is surrounded by uranium deposits that would make mining by Psychlo impossible. For this task, he captures a human and trains him to do the dirty work for him.

This turns out to be the worst idea he could have possibly had, and soon enough, the human creates a rebellion force and this group discovers a way to destroy both the Psychlo on Earth as well as nullify any later threats of retaliation from the planet Psychlo. Semi-annually, the Earth colony teleports personnel, goods, and coffins; in terms of the latter, all dead Psychlo are shipped home for burial upon their homeworld. It is during this routine operation that the human rebellion strikes. They succeed in packing several huge coffins with nuclear dirty bombs and "planet busters" with the hope of destroying the Psychlo homeworld. Upon the teleportation's firing, the human's then take over the Psychlo's own war planes, tanks, and weaponry to regain control of the Earth.

The dirty nukes and planet busters successfully burnt out Psychlo's atmosphere, killing all of its inhabitants and correctly erasing their threat potential by causing the race to effectively become extinct in the wild.

Psychlo Gun
Psychlo guns are basically a two-in-one weapon, with two barrels - one barrel fires a destructive shot and the other emitting a green pulse that stuns and knocks targets back.