Amphibious. The dragon can breathe air and water.

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

Frightful Presence. When the dragon is bloodied, each creature 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.

Multiattack. The dragon makes three Rend attacks. It can replace one attack with a use of Spellcasting to cast Mind Spike.

Rend. Melee Attack Roll: +13, reach 15 ft. Hit: 9 (1d8 + 5) Slashing damage plus 3 (1d6) Poison damage.

Poison Breath (Recharge 5–6). Constitution Saving Throw: DC 19, each creature in a 90-foot Cone. Failure: 63 (18d6) Poison damage. Success: Half damage.

Spellcasting. The dragon casts one of the following spells, requiring no Material components and using Charisma as the spellcasting ability (spell save DC 19):

At Will: Detect Magic, Mind Spike
1/Day Each: Dominate Person, Plant Growth

Legendary Action Uses: 3. Immediately after another creature’s turn, the dragon can expend a use to take one of the following actions. The dragon regains all expended uses at the start of each of its turns.

Mind Invasion. The dragon uses Spellcasting to cast Mind Spike.

Pounce. The dragon moves up to half its Speed, and it makes one Rend attack.