From Halopedia, the Halo wiki
The Skitterer is a fast scout walker used by the Banished. They are cheap, expendable vehicles, though their twin-linked beam cannons are surprisingly lethal given their size. Their most notable feature is that they can use a defend ability to set up a protective overwatch on other friendly units and act as a weapon turret and defense shield.
Harsh restrictions on AI research in the Covenant limited the development of autonomous weapon systems, though clever San'Shyuum technicians did find that carefully selected and pruned Lekgolo colonies could substitute for artificial minds in some applications. Though never widely used, combat machines such as the Skitterer proved this approach had merit, though the risk of aberrant gestalts in small colonies meant it never saw widespread use. "Colony" later adapted and perfected this technique, which allowed for the integration of Lekgolo with the Banished Locust and mass production of Skitterers without the behavioral issues that plagued earlier work. Skitterers were deployed by "Colony" against the crew of the UNSC Spirit of Fire in 2559 during the Second Ark Conflict.
Halo Wars 2
Skitterer upgrade: Focused Beam
In Halo Wars 2 Skitterers are exclusive units for "Colony" and can be made at Banished outposts once the leader power has unlocked them. Like other scout units the Skitterer can be used to gather resources. The number of Skitterers able to attach to a unit depends on the unit's size. For example a Scarab is able to have three Skitterers, a Mgalekgolo pair two Skitterers, and a Huragok one Skitterer. Once attached to the unit the Skitterer will only be destroyed if the host unit is destroyed. In addition to providing more health to the host unit the Skitterers will continue to attack enemies. Without a host unit Skitterers perform okay against infantry, vehicles, and structures, but poorly against aircraft. Once the Focused Beam upgrade has been purchased the Skitterer will perform well against infantry. In Blitz a Skitterer Mob, consisting of five Skitterers, costs 90 energy.
List of appearances