"I stood there... Gazing over the fields as they slowly progressed...
I couldn't decide whether to run or become... but if I didn't choose... Fate would..."
Everyone has heard of Zombie attacks on Earth, but who's heard of an infestation on an irken inhabited planet...
In the production of a defective irken on an irken populated planet, its pak began to slowly release a toxin into its body, terminating many of its basic needs as well as its own life support in its own body. Oddly enough, the toxin also kept the deteriorating individual alive, and allowed it to perform its most basic instincts.
After feeding on other irken individuals, their paks began to release the very same toxin, slowly transforming the small planet's civilization into flesh hungry monsters. The world is now hazardous and restricted by many irken fleets, as the irken zombies, unlike humans, are able to survive much longer with the unknown toxin in their systems. However, the Tallest consider extracting the toxin for irken experimentation, to make either bio-weapons or dangerous monster-like individuals.
However, there is an Easter Egg in this pic. Look closely.