A fire spite is a non-sentient insectoid life form named for its unique ability to project torrents of flame from their mouths. A swarm of them were responsible for wiping out the population of a human colony on Weller's World.
Fire spites are small insect-like organisms roughly the size of a human fist. They somewhat resemble beetles, sporting chitinous exoskeletons and wings providing them with the ability to fly.
The spites have a unique ability that has never been seen in any sort of organism: the ability to breathe fire. This fire resembles streams of lava, and is extremely hot, capable of setting a full-grown human on fire. Oddly, this fire does little damage to non-organic targets; when marines were inspecting the bodies of some of the spites' victims, only organic material seemed to be affected.
A swarm of fire spites terrorized a research colony on the planet Weller's World, where human scientists were studying Xenomorph XX121. With their firebreathing ability, the spites slaughtered the colonists, and soon after, conflicted with a contingent of Colonial Marines from the 39th Spaceborne, the Devil Dogs. Most of the squad didn't survive the incident, but a few were able to flee the planet.