Kaortic Hulk (CR 8)

Huge Magical Beast (Extraplanar)
Alignment: Always neutral evil
Initiative: +2 (Dex); Senses: blindsight 120 ft., Listen +9, and Spot +3

AC: 27 (-2 size, +2 Dex, +17 natural), touch 10, flat-footed 25
Hit Dice: 9d10+45 (94 hp)
Fort +11, Ref +10, Will +6
Speed: 40 ft.
Space: 15 ft./10 ft.
Base Attack +9; Grapple +25
Attack: Bite +16 melee
Full Attack: Bite +16 melee and 2 claws +10 melee
Damage: Bite 2d8+8, claws 2d6+4
Special Attacks/Actions: Spell-like abilities
Abilities: Str 27, Dex 15, Con 20, Int 2, Wis 13, Cha 6
Special Qualities: reluctant servant
Feats: Alertness; Iron Will; Lightning Reflexes; Weapon Focus (bite)
Skills: Jump +18, Listen +9, and Spot +3
Advancement: 10-16 HD (Huge); 17-27 HD (Gargantuan)
Climate/Terrain: Any
Organization: Solitary
Treasure/Possessions: None

Source: Dragon #330

Reluctant Servant (Ex): If a kaortic hulk is called into service through a spell or other effect, there is a 1% cumulative chance each round that it turns on the creature that summoned it.

Spell-like Abilities: 2/day - gaseous form, spider climb, invisibility, silence. Caster level 8th.

A kaortic hulk eats anything, even undead, constructs, or oozes. Despite its bulk, it attempts to use its spell-like abilities to maneuver itself into places where it couldn't normally reach, then attack its prey while initially invisible and within a sheath of silence.

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.