Xenomorph Runner

"It kills on sight and is generally unpleasant."

- Andrews, about the Dog Alien

The Dog Alien was the main antagonist of Alien 3. Inherently, it wanted to kill everything aboard the Fiorina ship. This particular alien was called Dragon.

Biography
It erupted from a rottweiler called Spike aboard the Fiorina and even as a chestburster began making trouble for the humans aboard the ship. It spits acid in Murphy's face, the owner of the dog, and causes him to fall into a large ventilation fan. It matures in the ventilation system and begins slaughtering everything it sees upon reach adulthood. The only it spares is Ripley, but that's only because an immature Xenomorph Queen sits dormant inside of her. The inmates aboard the prison ship eventually resolve to fight and kill the creature, which they succeed in doing by dousing it in molten led then again in cold water. The vast differences in temperature and the heat of the initial dousing cause the creature to expand and explore.

Biology
The Dog Alien had all the typical characteristics of a Xeno, however it's physiology was different in a way that allowed it to move faster than the average Warrior or Drone. In particular, it had a preference for walking on all fours and it's legs were shaped in a more digitigrade way for this purpose. Also, while those aliens affected a more black or blue-black coloration, the Dog Alien was dark brownish-red. It lacked the dorsal tubes and spines of it's warrior cousins and as a chestburster it was born with all of its limbs.

While all Xenomorphs have an aversion to fire, Dog Aliens are particularly affected by it. The heat causes them to expand internally and explode, showering nearby enemies with damage shrapnel.