GM Irae

 

Class: Moon of Impensus900px-Io_highest_resolution_true_color
Size: Medium
Gravity: Standard
Atmosphere: Low pressure Terran
Anomalies: Oxygen atmosphere is produced by photosynthesis of Centiworms, Extra solar xenos life form – Centiworm

Centiworm

Parasitical insect evolved in some unknown warp traveling vessel’s bilge. Invaded Irae  from passing which dumped it’s bilge on orbit of Impensus and became endemic species at the moon. Backround radiation is food source of Centiworm. Irae surface they are not able to grow bigger than huge. I fCentiworm finds good source to feed it may grow to gargantuan size.

Size: Small to Huge
Traits:
Sense heat
Poisonous, invulnerable to fire, vacuum, electricity, radiation, acid
Small: Can burrow through skin and invade internally.
Huge: Ferociosly hungry as solar radiation feeds it barely.

Story thread: Prison warden Vladir pays handsomely for alive specimens of centiworms. Bigger the centiworm, bigger the profit. His bounty bring steady amount of mercenaries capturing centiworms at Irae.