Fiery ammunition bursts into glowing embers when fired. While this is not enough to change its normal damage to fire damage, any extra damage from a critical hit is considered fire damage and the weapon deals half damage to targets that take half damage from energy attacks but no damage from kinetic attacks (such as incorporeal creatures) and counts as a weapon with the explode special property against creatures with swarm defenses. If fiery ammunition is used in a weapon that already deals half fire damage (such as a weapon with the flaming weapon fusion), on a critical hit, all the damage dealt is fire damage. At the GM’s discretion, fiery ammunition can set extremely flammable materials on fire, such as oil-soaked rags or dry tinder.