Covenant pest

There are Covenant Pests that can be found in Halo 2 level "Gravemind". On the three floors of the detention centre there are what looks like small insects crawling around the place. It is unkown how and where these little pests came from but some theories are that they are a food source for either lower species of the Covenant or are just pests, similar to cockroaches in a city apartment. This is quite unlikely due to the cleanliness seen throughout the rest of High Charity, especially the Sanctum of the Hierarchs. It is possible that they came from plant life that the Covenant brought from Installation 04 or that certain shipments from other planets brought them through the large metal storage crates seen throughout the city. The pest is very small and yellow. It seems to slide on the floor and on the walls, and once anyone approaches one, it slides away. They are able to be shot at, but are unable to be killed.

Other wildlife on High Charity, include what appear to be fish, in both the Hanging Gardens and in the Valleys of Tears; and birds similar to those found on the levels Delta Halo and Regret. This lends credit to the theory mentioned above that the Covenant pests were brought up from the Halo ring, since the birds also appear to have been brought from Halo.