Bake-kujira the Elder Beast of Forgotten & Dismissed

Echolocation. The whale can’t use its blindsight while deafened.

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

Multiattack. The whale makes two attacks: one with its bite and one with its gaze of pain.
Bite. Melee Weapon Attack: +11 to hit, reach 5 ft., one target. Hit: 16 (3d8 + 8) piercing damage and 12 (3d6) necrotic damage. If bitten a creature must make a Wisdom save DC 22 or be stunned for 1 minute. The target can repeat it's save at the end of each of it's turns or if it takes damage.
Gaze of Pain. The Bake-kujira gazes upon the living and undead alike, boring into them with gaze of burning pain and retribution. Targets in a 60ft cone must make a DC 24 Wisdom save or take 18 (6d6) psychic damage, half as much on a success. If underwater the targets are pushed back 10ft from the creature. 

Rising Tides: The Bake-kujira casts tidal wave at 3rd level. 

Water Whips: Range spell attack: +8 to hit. targets one creature, range 15ft, 6 (1d6+3) bludgeoning and 2 (1d4) necrotic damage. The Bake-kujira casts control water, creating 8 water tentacle like whips that each can make one attack on a creature.

Psychic Wail: The Bake-kujira emits a powerful psychic pulse of sound within 120ft of itself. Each creature in range must make a DC 26 Wisdom save or take 20 (2d10 +5) psychic damage, and be forced to fall prone under the weight of the creatures anguish. 

Fracturing Hunting Pack:  The Bake-kujira suffers 100 damage to itself as part of it's own body breaks away, the bones reforming and animating into two Giant Shark Skeleton monsters. These newly animated undead are friendly to the Bake-kujira and fallow it's orders that are communicated telepathically.