Taken from the Creature Codex
This enormous creature resembles a caricature of a whale—it is mostly mouth attached to a slug-like body. Its tail ends in a single immense pincer.
A slide-rock bolter’s scale beggars the imagination. This massive creature is about 100 feet long and weighs 250 tons. Its territory encompasses an entire mountain or mountain range, where it lies in wait for its prey. Despite its size, a slide-rock bolter needs to eat only once a month or so, and a man-sized meal is sufficient enough to sustain it. It does enjoy being better fed, however, and entire herds of wildlife or settlements of people can disappear down its gaping maw.
In combat, a slide-rock bolter is a match even for giants and dragons. Its body is coated in a thick layer of rock that protects it from all but the mightiest blows, and it is capable of swallowing even enormous creatures whole in the blink of an eye. Slide-rock bolters are ambush predators, hiding in plain sight as a cliff side or mass of boulders before launching themselves over their prey. Any enemies not killed outright by its bulk or devoured are picked off by its mighty jaws and clawed tail. Opponents that harass it from a distance are pelted with hurled boulders.
Silde-rock bolters are fortunately rare and solitary creatures. They reproduce asexually and only upon death—when a slide-rock bolter is slain, a geode-like stone inside its head begins to transform into an egg, which hatches a horse-sized baby bolter. Where the first slide-rock bolters came from is a mystery, although many sages suspect the Elemental Plane of Earth as an origin.
Slide-Rock Bolter CR 20
N Colossal aberration (earth)
Init +4; Senses blindsight 30 ft., darkvision 60 ft., Perception +17, tremorsense 120 ft.
AC 35, touch 2, flat-footed 35 (-8 size, +37 natural)
hp 362 (25d8+250), fast healing 10
Fort +20, Ref +10, Will +18
DR 20/adamantine; SR 31
Immune cold, disease, electricity, fire, poison
Speed 20 ft., climb 20 ft., sprint
Melee bite +25 (4d12+22/19-20 plus dispelling bite and grab), claw +25 (4d8+15)
Ranged rock +25 (4d6+22)
Space 30 ft.; Reach 30 ft.
Special Attacks crushing trample (8d12+22, DC 37), dispelling bite, fast swallow, gobble, mighty hurl, powerful blows (bite), rock throwing (200 ft.), swallow whole (AC 28, 72 hp)
Str 40, Dex 11, Con 30, Int 3, Wis18, Cha 7
Base Atk +18; CMB +41 (+45 grapple); CMD 51 (cannot be tripped)
Feats Cleave,Critical Focus, Great Cleave, Great Fortitude,Greater Vital Strike, Improved Critical (bite),Improved Initiative, Improved Vital Strike, Lightning Reflexes, Power Attack, Staggering Critical, Stunning Critical, Vital Strike
Skills Perception +17, Stealth +3 (+23 in rocky terrain); Racial Modifiers +20 Stealth in rocky terrain
Languages Terran (cannot speak)
SQ freeze (rock), massive movement, reinforced guts
Environment any mountains
Crushing Trample (Ex) Any creature that fails a Reflex save against a slide-rock bolter’s trample, or that forgoes the save in order to make an attack of opportunity, must succeed a DC 37 Fortitude save or be knocked prone and stunned for 1d4 rounds. The save is Strength based.
Dispelling Bite (Su) A creature bitten by a slide-rock bolter is affected by a greater dispel magic at CL 20th. This effect first targets spells and effects that prevent or protect against grappling, and then affects other spells as normal.
Gobble (Ex) When using its crushing trample ability, a slide-rock bolter can make a bite attack against any creature within its reach as a swift action. If it makes an attack against a creature that has taken damage from its trample, it gains a +4 bonus on the attack roll.
Massive Movement (Ex) Because a slide-rock bolter is so massive, uneven ground and other terrain features that form difficult terrain generally pose no significant hindrance to a slide-rock bolter’s movement, though areas of forest or settlements are considered difficult terrain to it.
Mighty Hurl (Ex) A slide-rock bolter uses its Strength score instead of its Dexterity score to modify its rock attack.
Reinforced Guts (Ex) A creature swallowed by a slide-rock bolter must deal damage equal to 1/5th the slide-rock bolter’s hp in order to cut its way out.
Sprint (Ex) Once per hour, a slide-rock bolter can move at ten times its base speed. It can use its crushing trample ability in conjunction with sprint.