Ultralisk
Huge Aberration (Zerg)
Hit Dice: 26d8+211 (328 hp)
Initiative: +5 (+1 Dex, +4 Improved Initiative)
Speed: 50 ft. (10 squares)
Armour Class: 29 (+1 Dex, -2 size, +20 natural), touch 9, flat-footed 28
Base Attack/Grapple: +19/+38
Attack: Kaiser blades +29 melee (3d6+11/18-20/x3)
Full Attack: Kaiser blades +29 melee (3d6+11/18-20/x3)
Space/Reach: 15 ft./10 ft.
Special Attacks: Trample.
Special Qualities: Darkvision 60 ft., damage reduction 10/-, fast healing 8, immunity to poison and cold, resistance to acid and eletricity 15, Zerg traits
Saves: Fort +18, Ref +9, Will +18
Abilities: Str 33, Dex 13, Con 27, Int 1, Wis 16, Cha 8
Skills: Hide -7, Intimidate +18, Listen +8, Spot +8
Feats: Cleave, Great Cleave, Great Fortitude, Improved Bull Rush, Improved Initiative, Improved Natural Attack, Power Attack, Toughness, Weapon Focus (kaiser blades)
Environment: Any
Organization: Solitary, pair, pack (3-7), or brood (100-200 Zerglings, 24-48 Hydralisks, and 3-7 Ultralisks)
Challenge Rating: 18
Treasure: None
Alignment: Lawful evil
Advancement: 27-39 HD (Huge), 40-52 HD (Gargantuan)
Level Adjustment: --

   The thundering beast stands on four huge legs. Large mandibles swing back and forth before its head, but more fearsome are the massive, bone-like scythes that protrude from its back.

Description
   Originally evolved from the massive but docile Brontolith, the dreaded Ultralisk is the most powerful of the Zerg ground forces, used like a battering ram to plow through all manner of enemy forces. More dangerous than any armoured vechicle, these lumbering monsters creatures are best dealt with from the air. A handful of these creatures are believed to have been responsible for the death of an entire Confederate garrison on Timul IV. Unlike smaller Zerg strains, these creatures are unable to burrow into the ground.

Combat
   The kaiser blades the creature swings from its back are nearly indestructible, and have a monomolecular edge, allowing them to tear through most known substances with ease, vehicles and infantry alike.
   Augmented Critical (Ex): An Ultralisk’s kaiser blades threaten a critical hit on a natural attack roll of 18–20, dealing triple damage on a successful critical hit.
   Trample (Ex): As a standard action, an Ultralisk can move up to 50 ft. and literally run over huge or smaller sized creatures. This attack deals 2d6+11 points of bludgeoning damage to anything in its path - a trampled opponent can attempt an attack of oppurtunity at a -4 penalty, or a Ref save (DC 31) for half damage.