Biting Wind

An eeire, high pitched whistling as if a giant breath blowing across a sea of crystal goblets sounds, with a lower, thrumming tone felt in the bones... which grows louder with astonishing speed...

Dimunitive Air Elemental (cold, swarm)
Hit Dice: 8d8 (36 hp)
Initiative: +13
Speed: Fly 200 ft. (perfect) (40 squares)
Armor Class: 23 (+8 dex, +1 natural, +4 size), touch 21, flat-footed 15
Base Attack/Grapple: +6/-
Space/Reach: 20 ft./0 ft.
Attack: Swarm (2d6 plus 1d6 cold)
Full attack: Swarm (2d6 plus 1d6 cold)
Special Attacks: Forceful blow, instinctive fear
Special Qualities: Air mastery, darkvision 60 ft., elemental traits, immune to cold and weapon damage, natural invisibilty, swarm traits, vulnerability to fire
Saves: Fort +2, Ref +15, Will +2
Abilities: Str 1, Dex 28, Con 11, Int 2, Wis 11, Cha 6
Skills: Listen +1, Spot +10
Feats: Flyby Attack, Improved Initiative, Run
Environment: Elemental Plane of Air
Organization: Swarm, Gust (1-20 swarms)
Challenge Rating: 5
Treasure: None
Alignment: Always neutral
Advancement: --
Level Adjustment: --

Biting wind is a collection of almost mindless air elementals that to most senses are instinguishable from normal wind. Until the wind hits them, tearing the flesh from their bones. Then it becomes apparent it is anything but normal.

If their natural invisibility is seen through they appear as a great cloud of vague, whispy bladed crystals with curling, thrashing tails.

Unless directed in some way a biting wind rarely does more than blow through once in its neverending flight from one place to the next. If controlled or in some way threatened or angered they will shoot past their foes repeatedly and then disapear out of range of most weapons before any can react. They will repeat this until they or their foe can no longer fight.

Air Mastery (Ex):
Biting wind gains a +4 bonus on its attack and damage rolls if its opponent is airborne.

Forceful Blow (Ex):
When a Biting Wind blows through it is treated as a temporary hurricane. Along with taking damage, unless a DC 20 fortitude check is made, medium or smaller characters are blown away, large creatures are knocked down, and huge creatures are checked (see p. 95 of the DMG).

Instinctive Fear (Ex):
Biting Wind produces a sound like that of an approaching tornado, which causes a primal dread in most non-mindless creatures. Those within 120 feet of a Biting Wind must make a DC 14 Will check or become shaken for the entire duration of their presence. Those who make the save are unaffected by the sound for the rest of the day. The save DC is constitution based.

Natural Invisibility (Ex):
Biting wind is effectively invisible as the spell.

Vulnerability to Fire:
Biting wind takes half again as much (+50%) damage as normal from fire spells and effects, regardless of whether a saving throw is allowed, or if the save is a success or failure.