Adult Phoenix

Fiery Death and Rebirth. When the phoenix dies, it explodes. Each creature within 60-feet of it must make a DC 20 Dexterity saving throw, taking 10d4 fire damage on a failed save, or half as much damage on a successful one. The fire ignites flammable objects in the area that aren't worn or carried.

The explosion destroys the phoenix's body and leaves behind an egg-shaped cinder that weighs 5 pounds. The cinder is blazing hot, dealing 6d6 fire damage to any creature that touches it, though no more than once per round. The cinder is immune to all damage, and after 1d10 days, it hatches a new phoenix.

Fire Form. The phoenix can move through a space as narrow as 1 inch wide without squeezing. Any creature that touches the phoenix or hits it with a melee attack while within 5 feet of it takes 1d10 fire damage. In addition, the phoenix can enter a hostile creature's space and stop there. The first time it enters a creature's space on a turn, that creature takes 1d10 fire damage and catches fire; until someone takes an action to douse the fire, the creature takes 1d10 fire damage at the start of each of its turns.

Flyby. The phoenix doesn't provoke opportunity attacks when it flies out of an enemy's reach.

Illumination. The phoenix sheds bright light in a 60-foot radius and dim light in an additional 60 feet.

Innate Spellcasting. The Phoenix can cast the following spells innately. Wisdom is it's spellcasting ability (spell save DC 19, +12 to hit, lvl 18 spellcaster)

At will: light, sacred flame

3/day each: fireball, mass cure wounds, wind wall

1/day each: etherealness, fire storm, heal

Multiattack. The phoenix makes two touch attacks.

Peck. Melee Weapon Attack: +12 to hit, reach 5 ft., one target. Hit: 2d6 + 6 fire damage. If the target is a creature or a flammable object, it ignites. Until a creature takes an action to douse the fire, the target takes 1d10 fire damage at the start of each of its turns.

Absorb Elements* (fire). The phoenix can use your own body to block some of the incoming energy, absorbing its effect on you. The creature must be within 20 feet of the phoenix.

Legendary Resistance (3/Day). If the phoenix fails a saving throw, it can choose to succed instead.

Phoenix Tears (1d4/Days). As an action, phoenix cry on a dying creature, stabilizing them and bringing them up to 1 hit point. The tears removes any effects on the target. These tears lose their magical properties at the start of next turn and regain use after a 1d4 days.

Power Word Heal* (1/Day). A wave of healing energy washes over the creature you touch. The target regains all its hit points. If the creature is charmed, frightened, cursed, paralyzed, or stunned, the condition ends. If the creature is prone, it can use its reaction to stand up.

*It can remove artifact effects.