Fiery Death and Rebirth. When the phoenix dies, it explodes in a burst of fire and magma. Each creature within 10 feet of it must make a DC 11 Dexterity saving throw, taking 17 (5d6) fire damage on a failed save, or half as much damage on a successful one. Flammable objects that aren't being worn or carried in that area are ignited.
The explosion destroys the phoenix's body and leaves behind an egg-shaped cinder, which weighs 5 pounds. The cinder deals 10 (3d6) fire damage to any creature that touches it, though no more than once per round. The cinder is immune to all damage, and after 1d6 days, it hatches a new phoenix.
Flyby. The phoenix doesn't provoke an opportunity attack when it flies out of an enemy's reach.
Heated Body. A creature that touches the phoenix or hits it with a melee attack while within 5 feet of it takes 3 (1d6) fire damage.