Akara, the Sapphithyst Dragon

Spellcasting (Psionics). The dragon casts one of the following spells, requiring no spell components and using Intelligence as the spell casting ability (DC 18, +9 spell attack).

1/day each:  blink, dispel magic, protection from evil & good, sending, dissonant whispers, meld into stone, telekinesis, scrying, teleportation circle, control water.

Body Equilibrium. The dragon can telekinetically adjust its weight and local gravity to allow it to walk on any surface at any angle.  The dragon can walk across water, up the side of a hallway, or even across the ceiling with no penalty.  This ability does not prevent damage from walking across a dangerous surface (lava or spikes, for example).

Legendary Resistance (1/Day). If the dragon fails a saving throw, it can choose to succeed instead.

Tunneler. The dragon can burrow through solid rock at half its burrow speed and can choose to leave a 10-foot-diameter tunnel in its wake.

Sapphithyst Resistance. The dragon is resistant to force, thunder, lightning, and psychic damage.

The dragon can use its Frightful Presence. It then makes two melee attacks in any combination between bite, claws, and tail (only one attack of each per action).

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 17 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.

Bite. Melee Weapon Attack: +12 to hit, reach 10 ft., one target. Hit: 18 (2d10 + 7) piercing damage plus 9 (2d8) force damage.

Claw. Melee Weapon Attack: +12 to hit, reach 10 ft., one target. Hit: 11 (1d8 + 7) slashing damage plus 3 (1d6) thunder damage.

Tail. Melee Weapon Attack: +12 to hit, reach 10 ft., one target. Hit: 15 (2d8 + 7) bludgeoning damage plus 9 (2d8) force damage and 3 (1d6) thunder damage.

Singularity Breath (Recharge 5–6). The dragon creates a shining bead of gravitational force in its mouth, then releases the energy in a 90-foot cone. Each creature in that area must make a DC 20 Strength saving throw. On a failed save, the creature takes 45 (10d8) force damage, and its speed becomes 0 until the start of the dragon's next turn. On a successful save, the creature takes half as much damage, and its speed isn't reduced.

Debilitating Breath (Recharge 5–6). The dragon exhales a pulse of high-pitched, nearly inaudible sound in a 60-foot-cone. Each creature in that cone must make a DC 18 Constitution saving throw. On a failed save, the creature takes 45 (13d6) thunder damage and is incapacitated until the end of its next turn. On a successful save, the creature takes half as much damage and isn't incapacitated.

Psychic Step. The dragon magically teleports to an unoccupied space it can see within 60 feet of it.

Sapphithyst Telekinesis. When the dragon is struck by a melee attack, it can instinctively unleash a blast of telekinetic power. When a creature that the dragon can see damages it, the dragon can use its reaction to force the creature to make a DC 18 Strength saving throw. On a failed save, a creature takes 20 (6d6) force damage and is knocked prone. On a successful save, the creature takes half as much damage and is not knocked prone.