Windghost (CR 15)

Huge Aberration
Alignment: Usually lawful
Initiative: +10 (+6 Dex, +4 Improved Initiative); Senses: true seeing, Listen +25, and Spot +25
Languages: Auran

AC: 21 (-2 size, +6 Dex, +7 natural), touch 14, flat-footed 15
Hit Dice: 18d8+72 (153 hp)
Fort +10, Ref +14, Will +13
Speed: Fly 30 ft. (good)
Space: 15 ft./10 ft.
Base Attack +13; Grapple +17
Attack: Bite +21 melee
Full Attack: Bite +21 melee
Damage: Bite 2d8+13
Special Attacks/Actions: Darkvision 60 ft., improved grab, spell-like abilities, swallow whole, windsong
Abilities: Str 28, Dex 23, Con 18, Int 15, Wis 14, Cha 19
Special Qualities: Fast healing 3, flight, immunities
Feats: Alertness; Combat Reflexes; Flyby Attack; Improved Initiative; Lightning Reflexes; Weapon Focus (bite)
Skills: Hide +19, Knowledge (arcana) +23, Listen +25, and Spot +25
Advancement: 19-32 HD (Huge); 33-54 HD (Gargantuan)
Climate/Terrain: Any temperate or warm land
Organization: Solirary, pair, brood (3-5), or swarm (6-10)
Treasure/Possessions: None

Source: Monster Manual II

Improved Grab (Ex): If a windghost hits an opponent that is at least one size category smaller than itself with a bite attack, it deals normal damage and attempts to start a grapple as a free action without provoking an attack of opportunity (grapple bonus +30). If it gets a hold, it can try to swallow in the next round. Alternatively, the wind-ghost has the option to conduct the grapple normally, or simply use its jaws to hold the opponent (-20 penalty on grapple check, but the windghost is not considered grappled). In either case, each successful grapple check it makes during successive rounds automatically deals bite damage.

Spell-Like Abilities: At will - antimagic field, dispel magic, spell turning. Caster level 16th; save DC 14 + spell level.

Swallow whole (Ex): A wind-ghost can swallow a single creature that is at least two size categories smaller than itself by making a successful grapple check (grapple bonus +30), provided it already has that opponent in its mouth (see Improved Grab, above). Once inside the windghost, the opponent takes 1d8+4 points of bludgeoning damage and 1d6+2 points of acid damage per round from the monster's stomach. A successful grapple check allows the swallowed creature to climb out of the stomach and return to the windghost's mouth, where another successful grapple check is needed to get free. Alternatively, a swallowed creature can try to cut its way out with either claws or a light piercing or slashing weapon. Dealing at least 25 points of damage to the stomach (AC 20) in this way creates an opening large enough to permit escape. Once a single swallowed creature exits, muscular action closes the hole; thus, another swallowed opponent must cut its own way out. A Huge windghost's stomach can hold 1 Medium-size, 4 Small, 16 Tiny, or 64 Diminutive or smaller opponents.

Windsong (Su): Two or more windghosts within 90 feet of each other can emit a harmonizing sonic drone that throws off the equilibrium of any creature that hears it. The sound causes any creature within 120 feet (except windghosts) that fails a Will save (DC 23) to take a -6 circumstance penalty on Concentration checks, a -8 enhancement penalty to Dexterity and move at half normal speed. These penalties remain as long as the windghosts continue to sing. A successful save renders a creature immune to that particular pair of windghosts' windsong for 24 hours. Windghosts can end a windsong at will.

Fast Healing (Ex): A windghost regains lost hit points at the rate of 3 per round. Fast healing does not restore hit points lost from starvation, thirst, or suffocation, and it does not allow the windghost to regrow or reattach lost body parts.

Flight (Ex): A windghost is naturally buoyant and can fly (as the spell) as a free action at a speed of 30 feet.

Immunities (Ex): Windghosts are immune to air and mind-affecting effects.

True Seeing (Su): A windghost sees all things as if affected by true seeing (arcane version).

Windghosts never attack without provocation. When threatened, they surround themselves with magical protections before swooping down to physically attack. If facing overpowering opponents, windghosts flee, flying straight up until they are out of sight.