Not every construct born of necron science was made for war in the traditional sense. Canoptek Scarabs are small, semi-autonomous machines originally designed as maintenance drones, tasked with repairing tomb complexes, tending to dormant warriors, and keeping the vast machinery of a necron dynasty running across the eons of the great sleep. Left to their own simple protocols for so long, these scarabs have developed an almost insectile swarm behavior, clustering and acting in loose, instinctive coordination.
When a tomb world wakes for war, these same swarms are unleashed against the enemy, skittering across the battlefield in dense, glittering clouds. Their mandibles and cutting limbs, designed to strip away corroded necrodermis and clear rubble, prove equally effective at tearing through the armor plating of enemy vehicles and disabling war machines from the outside in. A swarm descending upon a tank can reduce it to scrap with unsettling speed.
Because they are simple, mass-produced, and easily replenished from a tomb complex's reserves, Scarab swarms are deployed without hesitation, sent skittering ahead of the main advance to harass, disrupt, and consume anything mechanical that stands in the legion's path.