Made from the hollowed-out exoskeleton of an enormous centipede, this construct is reinforced with bands of steel and animated by steam-powered clockworks.
AC 21, touch 2, flat-footed 21 (+19 natural, –8 size)
Speed 60 ft., tunnel run
Str 43, Dex 11, Con —, Int —, Wis 10, Cha 2
Environment any land or underground
Breath Weapon (Su) Cloud of steam 20 feet high, 25 feet wide, and 50 feet long, once every 1d4 rounds, damage 12d6 fire, Reflex DC 19 half; can be used at full effectiveness underwater. The save DC is Constitution-based, and includes a +4 racial bonus.
Transport (Ex) The segments of a tunnel runner's body are hollowed-out spaces, each resembling the interior of a large cart. Gear can be carried by a tunnel runner as if it were wearing saddle bags, and creatures carried by a tunnel runner gain cover as if they were riding in chariots. Creature carried by a tunnel runner treat its body as a platform on which they can move around; they don't share the tunnel runner's space, even if they are using the tunnel runner as a mount.
Tunnel Run (Ex) Whenever a tunnel runner begins its turn with at least part of its space inside an archway or tunnel whose interior is no more than 10 feet wide, the tunnel runner's base speed increases to 120 feet until the beginning of its next turn.