Scrub (Earth-5875)

Scrubs are a small species of insect that tend to inhabit civilian and UNSC spaceships, feeding on its machinery, and are thus regarded as pests.

Anatomy and physiology
Scrubs are small, flight-capable arthropods, similar to the yanme'e, but much smaller and non-sapient. They have hairy backs and are anxious, including being potentially aggressive if provoked. Their hairs act like sensors that alert them from danger. During long interstellar travels, scrubs have to be contained in order to stop them from damaging a ship's system, hence the use of boarding cats as pest-controllers. They have brownish-green blood.