|The following is based on Fallout Tactics and some details might contradict canon.|
The crab-like scurry robot is a utility robot model that was most likely designed before the Great War. After the War, it was used by the Calculator, the mad A.I. from Vault 0, and adapted for combat.
Like many of the other smaller robots, they can be seen in a variety of locations. They patrol most open ground in robot-controlled areas. It has the ability to hide under the dirt and pop out just before unsuspecting victims and almost always appears in groups. Due to relying almost exclusively on ambush tactics, it prefers to attack up close and does not possess any ranged attacks.
Van Buren concept art
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