Earth Glider (CR 12)

Large Outsider (Earth, Evil, and Extraplanar)
Alignment: Usually neutral evil
Initiative: +2 (Dex); Senses: darkvision 60 ft., tremorsense, Listen +18, and Spot +18

AC: 29 (-1 size, +2 Dex, +18 natural), touch 11, flat-footed 27
Hit Dice: 15d8+75 (142 hp); DR: 5/bludgeoning
Fort +14, Ref +11, Will +9
Speed: 20 ft., burrow 50 ft.
Space: 10 ft./10 ft.
Base Attack +15; Grapple +28
Attack: Gore +23 melee
Full Attack: Gore +23 and bite +21 melee and 2 wing buffets +21 melee and 1 tail slap +21 melee
Damage: Gore 2d10+9, bite 2d8+4 plus poison, wing buffets (2) 1d6+4, 1 tail slap 2d6+4
Special Attacks/Actions: Poison
Abilities: Str 28, Dex 14, Con 21, Int 10, Wis 11, Cha 10
Special Qualities: earth glide, immunity to fire, resistance to electricity 10
Feats: Cleave; Diehard; Endurance; Great Cleave; Multiattack; Power Attack
Skills: Hide +16, Intimidate +18, Knowledge (dungeoneering) +18, Listen +18, Move Silently +20, Search +18, Spot +18, and Survival +18 (+20 following tracks or underground)
Advancement: 16-21 HD (Large); 22-45 HD (Huge)
Climate/Terrain: Underground
Organization: Solitary or pair
Treasure/Possessions: None

Source: Underdark

Poison (Su): Bite, Fortitude DC 22, initial and secondary damage 1d6 points of Charisma damage. An opponent reduced to 0 Charisma by the earth glider's poison is petrified, as is by the flesh to stone spell.

Earth Glide (Ex): An earth glider can glide through stone, dirt, or almost any other sort of earth except metal as easily as a fish swims through water. Its burrowing leaves behind no tunnel or hole, and its passage does not create any ripples or other signs of its presence. A move earth spell cast on an area the earth glider occupies flings it back 30 feet but has no other effect.

Tremorsense (Ex): An earth glider can automatically sense the location of any creature or object within 60 feet that is in contact with the ground.

Earth Subtype

This subtype usually is used for elementals and outsiders with a connection to the Elemental Plane of Earth. Earth creatures usually have burrow speeds, and most earth creatures can burrow through solid rock.

Evil Subtype

A subtype usually applied only to outsiders native to the evil-aligned Outer Planes. Evil outsiders are also called fiends. Most creatures that have this subtype also have evil 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 an evil alignment, no matter what its alignment actually is. The creature also suffers effects according to its actual alignment. A creature with the evil subtype overcomes damage reduction as if its natural weapons and any weapons it wields were evil-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.