Sunfly

(From Planescape: Morte's Planar Parade - 2023):

Sunflies are whimsical, buzzing inhabitants of the Outer Planes. They travel widely and are important indicators of the health of the realms in which they reside; when sunflies struggle, so do the places they inhabit. Sunflies have stingers that they use to inject natural toxins into other creatures. Planar magic can alter a sunfly’s toxin so that its effect is different depending on which Outer Plane the sunfly is on.

Many inhabitants of the planes have strong feelings about sunflies, viewing them as loathsome pests or adorable pets. Sunflies in Sigil are often the pets of doting, highly protective owners.

(From Book of Exalted Deeds - 2003):

Sunflies are native to the planes of good. Individually, they are used as messengers and couriers by archons, planar petitioners, and clerics of Pelor. They are only dangerous in swarms, gnawing on evil creatures that are dazzled by their celestial radiance. 

A sunfly resembles a large, golden dragonfly with an eldritch, otherworldly quality. Their legs are long and spindly, their eyes are bright and rainbow-colored, and their silvery wings are gossamer-thin. They also have mothlike antennae that catch sunlight like dew-coated spidersilk. 

Combat: The sunfly swarm surrounds and attacks anything that gets in its way. The swarm deals 2d6 damage to any creature or object whose space it occupies at the end of its move. 

The sunfly swarm’s natural attacks are treated as good weapons for the purpose of overcoming damage reduction. 

Dazzling Distraction (Ex): Any creature that begins its turn with a sunfly swarm in its square is automatically dazzled and, if living, must make a DC 13 Fortitude save or be nauseated for 1 round. The save DC is Constitution-based. 

Spell-Like Abilities: At will—detect evil (always active), detect evil (always active). Caster level 10th. 

Sunburst (Sp): Three times per day, a sunfly swarm can duplicate the effects of a sunburst spell cast by a 20th-level cleric with access to the Sun domain. A successful DC 19 Reflex save halves the damage and negates the blindness effect. The swarm cannot deal damage during the same round it uses the sunburst ability. The save DC is Wisdom-based. 

Sundance (Su): Once per round, a sunfly swarm can perform a dance that duplicates the effects of a protection from evil spell, affecting both the swarm and any creature occupying the same square. The swarm cannot deal damage during the same round it performs the sundance. 

Immunity to Light: Sunfly swarms are immune to harmful or debilitating light spells and effects, including all spells with the light descriptor. 

Outsider Traits: A sunfly swarm cannot be raised, reincarnated or resurrected (though a limited wish, wish, miracle, or true resurrection spell can restore life). Darkvision 60 ft. Sunflies do not need to eat or sleep. 

Swarm Traits: A swarm of sunflies is immune to weapon damage, critical hits, flanking, and spells that target a certain number of creatures (such as disintegrate). The swarm takes a –10 penalty on saving throws against spells or effects that affect an area, such as many evocation spells or grenadelike weapons. If the area effect attack does not allow a saving throw, the swarm takes double damage instead. Swarms are never staggered or reduced to a dying state by damage. Also, they cannot be tripped, grappled, or bull rushed, and they cannot grapple another. 

The swarm deals automatic damage to any creature whose space they occupy at the end of their move, with no attack roll needed. Swarm attacks are not subject to a miss chance for concealment or cover.

(From Planescape: Monstrous Compendium Appendix II - 1995):

Sunflies are tiny creatures native to the planes of good. They’re occasionally used as messengers or couriers by the local archons, aasimon, or petitioners. Sunflies also make excellent sentries and scouts, since there are a lot of ’em and they can cover a lot of ground quickly. However, for the most part sunflies have no desires or impulses other than creating wonderful dances of light and song, spreading joy and beauty wherever they go.

A sunfly resembles a large, golden dragonfly with an eldritch, other-worldly quality. Their legs are long and spindly, their eyes are bright and rainbow-colored, and their wings are gossamer-thin. They also have mothlike antennae that catch sunlight like dew-coated spidersilk. Humans who might otherwise be alarmed by the sight of such a large insect instead find the sunfly to be a beautiful, inoffensive, and fragile creature. By daylight, the sunfly’s golden carapace and silvery wings reflect the light in a dazzling array of color. At dusk, the insects release light they’ve stored all day long in a soft faerie glow. A sunfly’s wings produce a soothing hum or song in flight, changing pitch with each maneuver or shift of the wind.

Sunflies aren’t truly intelligent, but they’re highly empathic and have a sense for a creature’s alignment. Evil persons or monsters will be tormented unceasingly - sunflies are smart enough to go get a more powerful servant of good to deal with the intruders.

Combat: Sunflies resort to physical attacks only under the direst conditions. They’d much rather avoid conflict, and their high speed and maneuverability usually guarantee a quick escape. A really angry sunfly can bite for 1 point of damage.

Sunflies are capable of creating a dazzling burst of light once per hour. The victims must be looking at the sunfly and must be within 10 feet. If they fail saving throws versus spell, they’re blinded for 2d4 rounds. The sunfly prefers to use its physical attack against an opponent handicapped by dazzled vision. A cloud of sunflies often surrounds a party of intruders and flashes together to ensure that all of the possible targets are affected at once.

If there are 12 or more sunflies together, they can choose to perform a sundance instead of attacking or dazzling. By flying in a circular pattern, weaving and singing, the sunflies protect themselves and anything inside the pattern with a double-strength protection from evil. Sunflies can use this ability to trap evil creatures who can’t penetrate a protection from evil by weaving the sundance around them, preventing them from moving. The area protected by a sundance is one foot in diameter for each fly in the cloud, so a group of 25 sunflies can create a circle of protection 25 feet in diameter.

Habitat/Society: Sunflies are nomadic creatures, moving from place to place constantly. In a typical day a cloud of sunflies’ll migrate 15 or 20 miles. By night, the insects find a tree or bush to sleep in, curling up among the branches and dimming their lights to a faint gleam.

The more sunflies in a cloud, the more intelligent they seem to be. A large cloud can assign pickets or scouts to look for evil intruders, dispatch messengers to seek reinforcements, and use its collective dazzle and sundance ability to contain and confuse opponents until help arrives. The dances and songs performed by the sunflies grow more beautiful and intricate with each additional insect. As noted before, sunflies seem to have rudimentary know alignment and empathy abilities, and they can communicate surprisingly well by performing songs and dances for onlookers. The observer’ll pick up on a message of welcome, a warning of danger, or an invitation to play without even realizing that he’s deciphered the meaning of the display.

A sunfly cloud has no specific leaders. Decisions seem to be made by consensus. Sunflies are insatiably curious and may follow interesting people for hours, just to see what they’re doing.

Sunflies are prized for their beauty by the residents of the Upper Planes. It’s not uncommon for all work to stop in an Elysian town as the citizens gather in a nearby field to watch the sunflies dance at dusk. Any person familiar with sunflies knows that they keep their beauty only so long as they’re free; caging a sunfly brings about its death in a matter of hours.

Ecology: Sunflies live on small, mundane insects, fruit, and nuts or berries. Some sages speculate that their diets may be supplemented by an ability to derive nourishment from sunshine, just as plants do. Whether or not this’s true, it’s a fact that sunflies can’t be awakened at night — with one and only one significant exception.

Sunflies mate once a year, on midsummer eve or its closest equivalent in their current plane. The longest night of the summer is the only night of the year in which sunflies can remain awake, and they perform breathtaking dances from dusk to dawn. Sunflies always lay just one egg for each member of the cloud, concealing them on the topside of sunny leaves high in trees. The eggs hatch in 2 to 20 days, and the youg sunflies emerge as tiny golden moths — they never go through a larval stage. Sunflies grow to their full size in about 2 months, and can live for up to 10 years.