Scrub Grubs (Earth-4001)

Scrub grubs are a small species that inhabit at least one Covenant world. They tend to board space ships and feed on the machinery, and are often found on Covenant ships as pests.

History
The history of the scrub grubs is the same as their mainstream counterpart.

Biology
Scrub grubs are a type of arthropod, like the Yanme'e, though far smaller and non-sapient. They are anxious creatures with hairs that cover their turgid bodies. These hairs are always in motion, sensing for danger. On long space flights, their numbers have to be contained in order to prevent them from damaging any vital systems. When they are smashed they turn into a mealy liquid.

Trivia

 * The Covenant pests that can be seen on the level Gravemind in Halo 2 may be scrub grubs.