Mivilorn (CR 11)

Huge Magical Beast (Chaotic and Extraplanar)
Alignment: Usually chaotic neutral
Initiative: +1 (Dex); Senses: darkvision 60 ft., low-light vision, scent, Listen +7, and Spot +12

AC: 21 (-2 size, +1 Dex, +12 natural), touch 9, flat-footed 20
Hit Dice: 24d10+192 (324 hp)
Fort +22, Ref +15, Will +10
Speed: 40 ft.
Space: 15 ft./15 ft.
Base Attack +24; Grapple +42
Attack: Bite +17 melee
Full Attack: Bite +17 melee
Damage: Bite 4d6+30/19-20 plus 2d4 acid (Includes adjustments for Power Attack feat)
Special Attacks/Actions: Breath weapon, charging bite, improved grab, swallow whole
Abilities: Str 31, Dex 13, Con 26, Int 4, Wis 14, Cha 11
Special Qualities: SR 17
Feats: Alertness; Diehard; Endurance; Improved Bull Rush; Improved Critical (bite); Improved Overrun; Power Attack; Skill Focus (Listen); Track
Skills: Intimidate +10, Listen +7, Spot +12, and Survival +9
Advancement: 25-36 HD (Huge)
Climate/Terrain: Windswept Depths of Pandemonium
Organization: Solitary or herd (6-30)
Treasure/Possessions: None

Source: Monster Manual III

Breath Weapon (Su): 3/day - As a free action, a mivilorn can spew out digestive acid on its opponents. This breath weapon is a 15-foot cone, and it deals 5d4 points of acid damage to any caught in the area (Reflex DC 23 half). The save DC is Dexterity-based.

Charging Bite (Ex): When charging, a mivilorn opens its expansive mouth to its fullest width in order to swallow one or more opponents whole. If a mivilorn succeeds on a bite attack at the end of a charge, the victim must make a DC 23 Reflex save to avoid being scooped into the creature's expanded, open mouth. A mivilorn can scoop up a single Large creature, or two creatures of Medium or smaller size in the same attack if they are adjacent. In the latter case, the mivilorn makes one attack roll against the opponent with the higher AC. If the creature hits, both opponents take bite damage, and each gets its own Reflex save to avoid being trapped in the toothy cage. The save DC is Dexterity-based.

Improved Grab (Ex): In order to swallow an opponent without charging, a mivilorn must hit a Large or smaller opponent with its bite attack. It can then attempt to start a grapple as a free action without provoking attacks of opportunity. If is wins the grapple check, it establishes a hold and can try to swallow the foe the following round.

Swallow Whole (Ex): A swallowed creature automatically takes 6d4 points of bite damage every round in addition to the maximum damage from the mivilorn's acid attack (8 points). A mivilorn spews out any creature or creatures that succeed in dealing a total of 40 points of damage to its mouth (which has damage reduction 15/bludgeoning and an AC of 16). Trapped creatures may only use light melee weapons.

After 3 rounds of chewing on an opponent, a mivilorn spits it out to see if it is dead. If it's still alive, the mivilorn attempts to grapple and swallow the creature a second time.

When attacking from a distance, a mivilorn instinctively charges in order to use its charging bite special attack. A mivilorn's natural weapons are treated as chaotic-aligned for the purpose of overcoming damage reduction.

A mivilorn normally attacks using its Power Attack feat, taking a -15 penalty on its attack rolls and gaining a +15 bonus on damage rolls.

Chaotic Subtype

A subtype usually applied only to outsiders native to the chaotic-aligned Outer Planes. Most creatures that have this subtype also have chaotic alignments; however, if their alignments change they still retain the subtype. Any effect that depends on alignment affects a creature with this subtype as if the creature has a chaotic alignment, no matter what its alignment actually is. The creature also suffers effects according to its actual alignment. A creature with the chaotic subtype overcomes damage reduction as if its natural weapons and any weapons it wields were chaotic-aligned (see Damage Reduction).

Extraplanar Subtype

A subtype applied to any creature when it is on a plane other than its native plane. A creature that travels the planes can gain or lose this subtype as it goes from plane to plane. This book assumes that encounters with creatures take place on the Material Plane, and every creature whose native plane is not the Material Plane has the extraplanar subtype (but would not have when on its home plane). An extraplanar creatures usually has a home plane mentioned in its description. These home planes are taken from the Great Wheel cosmology of the D&D game (see Chapter 5 of the Dungeon Master's Guide). If your campaign uses a different cosmology, you will need to assign different home planes to extraplanar creatures.

Creatures not labeled as extraplanar are natives of the Material Plane, and they gain the extraplanar subtype if they leave the Material Plane. No creature has the extraplanar subtype when it is on a transitive plane; the transitive planes in the D&D cosmology are the Astral Plane, the Ethereal Plane, and the Plane of Shadow.