Encounters: Cormanthor - The Rimwood
Fyrefly Swarm (CR 4)
AC: 22 (+8 size, +4 Dex), touch 22, flat-footed 18
Hit Dice: 5d10 (27 hp)
Fort +4, Ref +8, Will +2
Speed: Fly 50 ft. (perfect)
Space: 10 ft./0 ft.
Base Attack +5; Grapple -
Full Attack: Swarm
Damage: 2d4 combustion (Ref save negates), 1 bite 80% chance
Special Attacks: Combustion, distraction
Abilities: Str 1, Dex 25, Con 8, Int 9, Wis 12, Cha 13
Special Qualities: immunity to fire, partial immunity to cold, vulnerability to water, swarm traits
Feats: Ability Focus (combustion), Alertness
Skills: Hide +20, Listen +5, Move Silently +8, and Spot +5
Climate/Terrain: Warm and temperate forest
Organization: 1000 (swarm)
Combustion (Ex): Any creature that begins its turn with a fyrefly swarm in its space must succeed on a DC 14 Reflex save or take an extra 2d6 points of fire damage as clothes ignite or armor becomes searing hot. The damage continues for another 1d6 rounds after the fyrefly swarm's last successful attack. Any flammable materials in a swarm's space also ignite immediately. The save DC is Constitution-based.
Distraction (Ex): Any living creature vulnerable to a swarm's damage that begins its turn with a fyrefly swarm in its space must succeed on a DC 12 Fortitude save or be nauseated for 1 round. The save DC is Constitution-based.
Partial Immunity to Cold (Ex): The fyrefly is partially immune to cold damage. Each time it would normally take damage from a cold attack, it takes no damage but instead falls into a catatonic coma for 24 hours. During this time, it cannot be awakened by any means. This is not a sleep effect.
Vulnerability to Water (Ex): Contact with water or a spell with the water descriptor has the same effect as its partial immunity to cold, except the fyrefly is allowed a DC 10 (or 10 + spell level) Fortitude save to negate the effect.
The adult fyrefly is not aggressive in the least. When it comes into contact with anything flammable, it sets objects ablaze, and it can use this ability to defend itself - unless it is in a swarm.
Generally, fyrefly swarms form only on starry nights. They attack randomly until the sun rises, they're defeated in combat, or 2d4 hours pass, whichever occurs first. The swarm sets afire all flammable substances it touches.
A victim in contact with the swarm has an 80 percent chance per round of being stung or bitten, suffering 1 point of damage. Additionally, he has a 100 percent chance of suffering 2d4 points of fire damage, unless he saves (Reflex), in which case he suffers no damage. A victim within five feet of the swarm must save (Reflex) or suffer 1d4 points of heat damage.
Each point of damage inflicted on the swarm kills 1d20 fyreflies. If half the swarm is killed, the survivors scatter. Darkness and similar spells that completely or partially obscure the swarm's view of the stars also scatter them.