Swarm of Clockwork Roaches

Swarm of Clockwork Roaches
Clockwork Roaches were a triumph of the early Steam-Wrights—tiny, self-replicating automata designed to crawl into the tightest crevices of Aether-Engines to clear soot and tighten loose bolts. However, after the "Great Re-Calibration," many of these swarms lost contact with their master-controllers. Left to their own devices, their programming warped. They no longer distinguish between a loose bolt and a knight's plate armor.
Behavior
A swarm of Clockwork Roaches sounds like a thousand clicking sewing machines. They move with a terrifying, synchronized efficiency. When they find a source of refined metal, they descend upon it, using high-speed vibration mandibles to "un-weave" the metal at a molecular level.
Infestation
Infestations are a major hazard in Steamfort's lower sectors. A single roach is a nuisance; a swarm can strip a steam-carriage to its chassis in minutes. The Kobolds of the Great Network have learned to lure these swarms toward dwarven fortifications, using them as living, metal-eating siege engines.
Weaknesses
While resistant to most physical attacks, the roaches are vulnerable to extreme heat or cold, which jams their delicate internal gears. A well-placed Shocking Grasp can also cause a short-circuit that ripples through the entire swarm, momentarily paralyzing them.