Flyby. The dragon doesn't provoke opportunity attacks when it flies out of an enemy's reach.
Unusual Nature. The dragon doesn't require air.
Multiattack. The dragon makes one Bite attack and one Tail attack.
Bite. Melee Weapon Attack: +9 to hit, reach 10 ft., one target. Hit:12 (2d6 + 5) piercing damage plus 7 (2d6) radiant damage.
Tail. Melee Weapon Attack: +9 to hit, reach 15 ft., one target. Hit:8 (1d6 + 5) bludgeoning damage.
Photonic Breath (Recharge 5–6). The dragon exhales a flashing mote of radiant energy that travels to a point the dragon can see within 120 feet of itself, then blossoms into a 20-foot-radius sphere centered on that point. Each creature in the sphere must make a DC 17 Constitution saving throw, taking 44 (8d10) radiant damage on a failed save, or half as much damage on a successful one.
A solar dragon (also known as a radiant dragon or a sun dragon) is born in the heart of a star. It divides its time outside its lair between patrolling its territory and hunting for food. The dragon has a serpentine body, a pair of ventral limbs ending in long fins, nebulous wings that give off light, and gleaming, multicolored scales. It can see clearly even in blindingly bright light.