Belker (CR 6)

Large Elemental (Air and Extraplanar)
Alignment: Usually neutral evil
Initiative: +5 (Dex); Senses: darkvision 60 ft., Listen +7, and Spot +7

AC: 22 (-1 size, +5 Dex, +8 natural), touch 14, flat-footed 17
Hit Dice: 7d8+7 (38 hp)
Fort +3, Ref +10, Will +2
Speed: 30 ft., fly 50 ft. (perfect)
Space: 10 ft./10 ft.
Base Attack +5; Grapple +11
Attack: Wing +9 melee
Full Attack: 2 wings +9 melee and bite +4 melee and 2 claws +4 melee
Damage: Wing 1d6+2, bite 1d4+1, claw 1d3+1
Special Attacks/Actions: Smoke claws
Abilities: Str 14, Dex 21, Con 13, Int 6, Wis 11, Cha 11
Special Qualities: elemental traits, Smoke form
Feats: Alertness; Multiattack; Weapon Finesse (wing)
Skills: Listen +7, Move Silently +9, and Spot +7
Advancement: 8-10 HD (Large); 11-21 HD (Huge)
Climate/Terrain: Elemental Plane of Air
Organization: Solitary or clutch (2-4)
Treasure/Possessions: None

Source: Monster Manual

Smoke Claws (Ex): A belker in smoke form (see below) can engulf opponents by moving on top of them. It fills the air around one Medium-size or smaller opponent without provoking an attack of opportunity. The target must succeed at a Fortitude save (DC 14) or inhale part of the creature. Smoke inside the victim solidifies into a claw or talon and begins to rip at the surrounding organs, dealing 3d4 points of damage per round. The affected creature can attempt another Fortitude save each subsequent round to cough out the semi-vaporous menace.

Smoke Form (Su): Most of the time a belker is more or less solid, but at will it can assume a smoke form. It can switch forms once a round as a free action and can spend up to 20 rounds per day in smoke form. A belker in smoke form can fly at a speed of 50 feet (perfect maneuverability). The ability is otherwise similar to a gaseous form spell cast by a 7th-level sorcerer.

In most cases, a belker fights with its nasty claws and painful bite.

Air Subtype

This subtype usually is used for elementals and outsiders with a connection to the Elemental Plane Air. Air creatures always have fly speeds and usually have perfect maneuverability (see the section on Movement).

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.