Astral Whale

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

Astrolocation. The whale can't use its truesight while deafened.

Dimensional Breath. The whale can stay in the Astral Plane for 5 hours before entering into another plane to inhale Planar Energy before diving back into the Astral plane.

Keen Hearing. The whale has advantage on Wisdom (Perception) checks that rely on hearing.

Plane diving. Warps into to the different planes of the multiverse for 1 hour before re entering the Astral plane. 

Bite. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. 5d10+4 piercing damage.

Headbutt (1 Action). Melee Weapon Attack: +5 to hit, reach 10 ft., one target. 5d12+4 bludgeoning damage.

Astral Surge (Recharge 5-6). Ranged Attack: +5 to hit, range 45 ft., one target. 2d12+20 psychic 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 21 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.