Rock borers are rare worm-like beasts that dwell underground in dry, rocky areas. They dig narrow, barely noticeable lairs and lurk near natural caves and passageways, bursting forth when they sense any sort of motion passing by their hiding place. As a result, they almost always attack with surprise. A rock borer can use its burrow speed even through the hardest of natural stone, since its acid softens the stone momentarily as the borer passes through.