Naga, Bone (CR 15)

Large Undead (Augmented Aberration)
Alignment: Always evil
Initiative: +6 (+2 Dex, +4 Improved Initiative); Senses: darkvision 60 ft., Listen +15, and Spot +15
Languages: telepathy 250 ft.

AC: 17 (-1 size, +2 Dex, +6 natural), touch 11, flat-footed 15
Hit Dice: 9d12 plus 6d12 (58 hp); DR: 5/bludgeoning
Fort +10, Ref +14, Will +18
Speed: 40 ft.
Space: 10 ft./5 ft.
Base Attack +9; Grapple +15
Attack: Sting +12 melee
Full Attack: Sting +12 melee and bite +7 melee
Damage: Sting 2d4+2 plus poison, bite 1d4+1 poison
Special Attacks/Actions: Poison, spells
Abilities: Str 14, Dex 15, Con -, Int 16, Wis 15, Cha 18
Special Qualities: detect thoughts, guarded thoughts, immunity to cold and poison, resistance to charm, SR 25
Feats: Alertness; Combat Casting; Dodge; Eschew Materials; Improved Initiative; Lightning Reflexes; Spell Focus (evocation)
Skills: Bluff +20, Concentration +15, Diplomacy +12, Disguise +5 (+7 acting), Intimidate +6, Knowledge (arcana) +12, Listen +15, Sense Motive +10, Spellcraft +25, and Spot +15
Advancement: 10-13 HD (Large); 14-27 HD (Huge) or by character class
Climate/Terrain: Temperate hills
Organization: Solitary, pair, or nest (3-4)
Treasure: Standard

Source: Serpent Kingdoms

This skeletal creature looks like a giant undead snake, except for its humanlike skull and long, deadly fangs. Its tail ends in a bony stinger.

This example uses a 6th-level dark naga sorcerer as the base creature. Created by a rival hundred of years ago as a guard, this bone naga despises both its master and its condition.

A bone naga is a skeletal undead creature created from a naga by a spellcaster (usually of its own race). A create undead spell can produce a bone naga from any naga subject with fewer Hit Dice than the creator.

A bone naga looks like a serpentine skeleton and typically measures about 12 feet long. Its skull bears an eerie resemblance to that of a human, except that it sports long fangs. A cold, cruel light burns in the creature's eye sockets, giving it an air of unspeakable hatred and malice. Its tail ends in a vicious bone stinger.

Though it despises servitude, a bone naga unswervingly obeys its creator, attacking even other nagas if so commanded. Should its master die, the bone naga becomes free-willed and can choose its own destiny.

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.