Taken from an actual Scandinavian myth that the aurora was really just the reflection of herring scales, and that was the name of the aurora borealis, Herring Flash.
Tiny Magical Beast (swarm)
Hit Dice: 10d10+40 (95 hp)
Speed: Fly 40 ft. (8 squares)(good)
Armor Class: 20 (+3 dex, +5 force, +2 size), touch 20, flat-footed 17
Base Attack/Grapple: +10/-
Attack: Swarm (1d8 bludgeoning plus prismatic touch)
Full attack: Swarm (1d8 bludgeoning plus prismatic touch)
Space/Reach: 20 ft./0 ft.
Special Attacks: Blinding scales, herring flash
Special Qualities: Blindsight 60 ft., energy resistance, harmony of energy, immune to blindness and electricity, resistance to fire 10, resonant flight, scent, thin-gilled
Saves: Fort +7, Ref +7, Will +3
Abilities: Str 5, Dex 16, Con 19, Int 1, Wis 12, Cha 9
Skills: Listen +6, Spot +6
Feats: Flyby Attack, Hover, Improved Initiative, Wingover
Environment: Any cold or temporate
Organization: Swarm, Glimmer (2-6 swarms), Aurora (10-18 swarms), Aurora Profundis (40-60 swarms)
Challenge Rating: 12
Alignment: Always neutral
Level Adjustment: --
Many tales of polar climes in both the north and south tell of the flash herring; flying fish of scintillating colors that are often mistaken for auroras. Only the occasional hurt or sick herrings ever fall, and upon dying go out quickly. In the rare instance when these herrings plummet into water, cushioning the fall, are they found still glowing, but they quickly drown, being unused to water.
Flash herring are the same shape as common herrings, but blaze with fierce, blinding colors. Swarms normally keep to the same color as their neighbors, but if one changes, so does all around until the entire cloud of herrings have adjusted. Flash herring always know when another is part of their swarm, so if another swarm approaches they may even mingle, but will not adopt the other's colors except when coincidence brings them to the same shade.
They survive many miles above the surface, and often actually mingle with true aurora, feeding off the electrically charged energy provided. These swarms appear far larger than they actually are, their light flaring out hundreds of feet past their bodies.
Flash herrings don't fight, they simply go their course and woe betide any whom get in their way. This course is erratic and ever changing, with one never knowing which direction the herring will go.
The swarm deals damage as seen under their Herring Flash ability to any creature whose space it occupies at the end of its move.
Blinding Scales (Ex):
One within 20 feet of a Flash Herring swarm with 8 HD or less are automatically blinded for 2d4 rounds (no save) at the end of which they are considered Dazzled for the entire time they are within range plus 1d4 minutes. Those with more than 8 HD are not blinded but still considered Dazzled. Flash herring can be seen from miles away, and provides illumination as a daylight spell at all times.
Energy Resistance (Ex):
Such is the disruption of forces around a flash herring that a mage must make a DC 20 caster level check to overcome the force. This is similar to spell resistance but only works on spells dealing with energy, such as fireball or lightening bolt. If unsuccessful the energy merely dissipates.
Harmony of Energy (Ex):
The make of a flash herring is such that it can pass through fields of force and prismatic walls as if it was water, the force being reflected back and bending around the fish. It does daze the swarm for 1d6 rounds however as the two energies resonate with one another.
Herring Flash (Su):
Flash herring's flashes of energy change in nature every 1d100 rounds. This energy is determined at random. The effect of the swarm is based on their color, as shown on the following table:
Resonant Flight (Ex):
d8 Color Effect
1 Red 3d6 points of fire damage
2 Orange 3d6 points of acid damage
3 Yellow 3d6 points of sonic damage
4 Green 6d6 points of damage (as disentegrate spell; Fortitude DC 10 half)
5 Blue 3d6 points of cold damage
6 Indigo 3d6 points of negative energy damage
7 Violet 3d6 points of electricity damage
8 White 3d6 points of force damage
Flash herrings are unmagically buoyant, lifting upwards on the natural magnetic forces of their world. They can lift very little more than their own weight and so are unusable for hauling purposes. Those in the southern hemisphere of a world are charged differently than flash herrings in the north and both fall immediately upon nearing the equator.
Flash herrings do not suffer from altitude sickness, and only in areas of no air at all do they suffer from suffocation.