Firestar

Also called moon dancers, firestars look like silent balls of light about the size of a fist, floating through wooded hills. Travelers often take them for will o' wisps or distant torches. A firestar can dim itself at will from torch-bright to complete darkness, which makes it effectively invisible. Kill one and the glow goes out for good, revealing the true body: a 2-inch egg shape netted in black, spidery nerves that meet at clusters of nodes and eyes.

Firestars never start fights. When attacked, one fires a small bolt of electricity up to 30 feet, five times a day, dealing 2d6 with no saving throw; the bolt travels through metal.

Flame feeds it. Any normal or magical fire aimed at it adds hit points equal to the damage it would have dealt to someone else, so a 12-hit-point firestar caught in an 18-point fireball rises to 30. It can reach at most four times its original total; anything beyond that bleeds away harmlessly, and the bonus fades after 1d4+1 hours. A flametongue sword feeds it only 1 hit point per strike, and flaming weapons generally both hurt and heal it at once. It also draws 2d6 hit points per round from a campfire or 1d6 from a torch, or it can hover motionless and swallow an entire fire in one go for 5d6 points, putting it out. Sparks within 20 feet drift toward it and vanish, which can give away a darkened firestar.

Electricity cannot hurt it, and most spells fail against it. Exceptions are magic missile, cold magic and spells of detection or communication, all of which work normally. Ordinary weapons can strike it.

These utterly alien beings spend their nights weaving intricate patterns with their companions among the trees and hills. They are mildly curious about the world but pay no mind to animals or travelers. Artificial light and magic draw them: they drift over to check out any campfire or magical light within two miles and any spellcasting within 200 yards. Most clashes begin with a misunderstanding: travelers take them for wisps or torches and attack. A hurt firestar may also seek out a camp on its own to drain the fire and heal.

They talk among themselves with complex flashes and shifts in brightness, and they follow some humanoid languages, gestures and movements. Though intelligent, they are shy and converse only with telepaths or through speak with monsters. They keep their life span and breeding secret; budding is suspected.

By day they settle in high, hard-to-reach places, pull in their glowing nerves and soak up sunlight and warmth. Resting firestars resemble exotic, decorated eggs, and treasure hunters sometimes pocket them to sell, only to have the 'eggs' wake at nightfall and try to escape.

Several of a firestar's organs are prized by spellcasters. One distinctive organ serves as a component for dancing lights, and every organ in it can go into scroll inks for detect magic, dancing lights or affect normal fires. Each organ fetches 1 to 5 gp.