They resemble Terran crabs, but are two meters wide with six legs, two large fighting arms ending in claws, and two manipulator arms. It is also possible to wire weapons directly into their nervous system, often launchers of flechettes or acid grenades. They have triple eyestalks and grinding mouths on their bellies. Their blood is copper-based and is blue.
Their frontal armor is extensive and requires armor-piercing weapons weapons instead of laser weapons or MACs. Essentially, they are living armored vehicles.
They have also evolved a "king crab," which serves as a leader that integrates them into a unit, making them more efficient warriors.
Common tactics include using their largest fighting claw as a shield and if possible, will try and dismember their foes.