Earth Necromental, Large* (CR 6)

Large Undead (Augmented Elemental, Earth, and Extraplanar)
Alignment: Always neutral evil
Initiative: -1 (Dex); Senses: darkvision 60 ft., Listen +6, and Spot +5

AC: 20 (-1 size, -1 Dex, +12 natural), touch 8, flat-footed 20
Hit Dice: 8d12 (52 hp); DR: 5/-
Fort +8, Ref +1, Will +2
Speed: 20 ft.
Space: 10 ft./10 ft.
Base Attack +6; Grapple +17
Attack: Slam +12 melee
Full Attack: 2 slams +12 melee
Damage: Slam 2d8+7 plus energy drain
Special Attacks/Actions: Create spawn, earth mastery, energy drain, push
Abilities: Str 25, Dex 8, Con -, Int 1, Wis 10, Cha 1
Special Qualities: earth glide, elemental traits, fast healing 3, undead traits
Feats: Cleave; Great Cleave; Great Fortitude; Power Attack
Skills: Listen +6 and Spot +5
Advancement: 9-15 HD (Large)
Climate/Terrain: Elemental Plane of Earth
Organization: Solitary
Treasure: None

Source: Libris Mortis

This walking pile of crumbling earth and stone radiates a palpable aura of death.

A necromental is the undead remnant of an elemental creature. It retains only a fraction of the self-awareness that the elemental had in life, but it becomes twisted and evil.

Augmented Subtype

A creature receives this subtype whenever something happens to change its original type. Some creatures (those with an inherited template) are born with this subtype; others acquire it when they take on an acquired template. The augmented subtype is always paired with the creature's original type. For example, a wizard's raven familiar is a magical beast (augmented animal). A creature with the augmented subtype usually has the traits of its current type, but the features of its original type. For example, a wizard's raven familiar has an animal's features and the traits of a magical beast.

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.

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.

This is a sample creature derived from a Template.