Adult Verdant Fog-Born Dragon

High Fliers. The dragon can breathe in an area that has any amount of air, no matter how thin. It can hold its breath for up to an hour at a time.

Verdant Scales. The dragon's flight speed is doubled while in clean air. In clean air, if the dragon moves at least 60 feet in a straight line before attacking, the attack deals an additional 21 (6d6) damage. Effects, climates, or conditions which pollute or exist instead of air; including but not limited to volcanic eruptions, the Fog Cloud spell, the smoke of a forest fire, and the dragon being underwater are considered to not be clean air for the purposes of this trait.

Fade Into Fog. The dragon can use its action to shapechange into a mass of semisolid air (or back to its dragon form). While in this form, the dragon makes stealth checks at advantage and loses its walking and swimming speeds, but gains the hover property.

Spellcasting. The dragon is an innate spellcaster. Its spellcasting ability is Charisma (spell save DC 18, +10 to hit with spell attacks). The dragon knows the following spells and can cast them at their lowest levels without material or somatic components:
Cantrips (at will): Lightning Lure, Shocking Grasp, Mage Hand, Spare the Dying

5x/day: Witch Bolt, Chromatic Orb (always chooses lightning damage)

3x/day: Lightning Bolt

1x/day: Storm Sphere, Chain Lightning

Multiattack. The dragon makes three attacks: one with its bite and two with its tail.

Bite. Melee Weapon Attack: +13 to hit, reach 10 ft., one target. Hit: 19 (2d10+7) piercing damage plus 14 (3d8) lightning damage.

Tail. Melee Weapon Attack: +13 to hit, reach 15 ft., one target. Hit. 21 (2d12+7) bludgeoning damage.

Cloud Breath (Recharge 5-6). The dragon exhales thick green fog and lightning in a 120ft long, 10ft line wide line in front of it. Each creature in that area must make a DC 18 Dexterity saving throw, taking 70 (14d8) lightning damage on a failed save, or half as much damage on a successful one. Creatures who fail the saving throw suffer effects similar to the slow spell for one minute.

Dash 3x/day. The dragon can take the dash action as a bonus action.

Outmaneuver. The dragon may use its reaction to move up to half its speed when another creature enters its reach. This movement doesn't provoke opportunity attacks.