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

Innate Spellcasting (Psionic). The dragon’s innate spell casting ability is Intelligence (spell save DC 19). It can innately cast the following spells, requiring no components:

At will: detect thoughts, levitate

1/day each: dominate monster, plane shift (self only)

Multiattack. The dragon can use its frightful presence. It then makes three attacks, two with its claws and one with its tentacles.

Claw. Melee Weapon Attack: +13 to hit, reach 5 ft., one target. Hit: 15 (2d8 + 7) slashing damage.

Tentacles. Melee Weapon Attack: +13 to hit, reach 15 ft., one creature. Hit: 15 (2d10 + 5) psychic damage. If the target is Huge or smaller, it is grappled (escape DC 17) and must succeed on a DC 18 Intelligence saving throw or be stunned until this grapple ends.

Extract Brain. Melee Weapon Attack: +13 to hit, reach 5 ft., one creature. Hit: 50 (10d10) piercing damage. If this damage reduces the target to 0 hit points, the dragon kills the target by extracting and devouring its brain.

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 18 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.

Mind Blast (Recharge 5–6). The dragon magically emits psychic energy in a 60-foot cone. Each creature in that area must make a DC 19 Intelligence saving throw or take 65 (12d10 + 5) psychic damage and be stunned for 1 minute. A creature can repeat the saving throw at each of its turns, ending the effect on itself on a success.

The dragon can take 3 legendary actions, choosing from the options below. Only one legendary action 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.

Tentacle. The dragon makes an attack with its tentacles.

Detect Thoughts. The dragon casts detect thoughts.

Psychic Scream (Costs 2 Actions). The dragon emits a wave of psionic energy 30 feet in all directions around it. Each creature with an Intelligence score of 4 or higher within that area must make a DC 19 Intelligence saving throw, taking 13 (2d8 + 5) psychic damage on a failed save, or half as much on a successful one. The dragon then teleports up to 40 feet away.