The Arachnaroks are lumbering monsters of chitin and dripping fangs. They crawl forth from bone-filled pits, over the accumulated corpse mounds of the Grots' offerings, ravaging any army they are sent against. Blades, bolts and bullets are turned from their thick hides as their legs spear warriors, driving them into the ground before the Arachnaroks sink gigantic fangs into them. On the Arachnaroks’ backs, the Spiderfang Grots mount crude howdahs. These are sometimes used to carry catapults that fling spider-filled webs at their enemies, and often serve as platforms for their wizards to unleash their stinging green sorcery.
By ingesting the venom of spiders, Grots can see into the minds of Arachnaroks and control them.