Burning Day

The phoenix is immune to any effect which would kill it outright, such as a basilisk’s Death Gaze. If the phoenix is reduced to 0 hit points, its body bursts into flames and it transforms into a phoenix hatchling. Any creature within 5 ft. of the phoenix must make a DC 12 Dexterity saving throw, taking 3 (1d6) fire damage on a failed save, or half as much on a successful one.