Adult tun mi lung (typhoon dragon)

Air and water immunity. The tun mi lung is immune to all attacks and effects based on air or water. 

Divine winds (1/week). As an action, In a 35 mile radius centered on the adult tun mi lung has very harsh winds and any objects that are not as tough as stone will be taken by the typhoon created by the winds and any creature not under cover must make a dc 15 Strength saving throw. On a failed save a creature is picked up by the winds and lifted 1d20 x 15ft up in the air and thrown in a random direction 1d12 x 15ft away and they take the resulting fall damage. This effects a creature every second round and the typhoon dragon is required to concentrate on this as if it was a spell  and has a duration of 6d4 hours average of 45 (15d6) bludgeoning damage. 

Flight orb. Though wingless, tun mi lungs can fly magically due to a magic black pearl embedded in their brains. If removed from the dragon, this pearl loses its magic but is still worth 1,000 gp. The dragon can cease or resume flight as a free action.

Magic Resistance. The tun mi lung has advantage on saving throws against spells and other magical effects.

Amphibious. The tun mi lung can breathe air and water.

Detect thoughts. The tun mi lung is constantly detecting the thoughts of creatures within 20ft of them. See the spell of the same name if a creature attempts to resist. 

Alternate form. Lung dragons can assume any humanoid form of Small to Large size as a standard action. This ability is similar to the polymorph spell but allows only humanoid forms. Whilst in this form they have advantage on all checks to hide their true self. 

Innate Spellcasting. The adult tun mi lung's innate spellcasting ability is Wisdom (spell save DC 19). The adult tun mi lung can innately cast the following spells, requiring no material components:

At will: invisibility, plane shift

3/day: darkness, lightning

Multi attack. The adult tun mi lung uses its frightful presence, bite and two claw attacks. 

Bite. Melee Weapon Attack: +15 to hit, reach 15 ft., 1 target. Hit: 18 (3d6 + 9) piercing damage. 

Claw. Melee Weapon Attack: +15 to hit, reach 5 ft., 1 target. Hit: 13 (1d8 + 9) slashing damage. 

Tail. Melee Weapon Attack: +15 to hit, reach 15 ft., 1 target. Hit: 14 (1d10 + 9) bludgeoning damage. 

Frightful Presence. Each creature of the dragon’s choice that is within 120 feet of the dragon and aware of it must succeed on a DC 19 Wisdom saving throw or become frightened for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a creature’s saving throw is successful or the effect ends for it, the creature is immune to the dragon’s Frightful Presence for the next 24 hours. 

The dragon can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time, and only at the end of another creature’s turn. The dragon regains spent legendary actions at the start of its turn.

Detect. The dragon makes a Wisdom (Perception) check.

Tail Attack. The dragon makes a tail attack.

Booming thunder (Costs 2 Actions). The dragon beats its long tail against the ground making a thunderous booming sounds and each creature within 60ft must make a dc 19 Constitution saving throw or be deafened for 1 minute. On a failed save the target can remake the save at the end of their turn.