Bearwhale

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

Hold Breath. The Bearwhale can hold its breath for 90 minutes.

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

Keen smell: The Bearwhale has advantage on wisdom (perception) checks that rely on smell 

Swift swimmer:The Bearwhale can use it's bonus action while in the water to either: Dash, hide, or disengage.

Bulwark Force: The Bearwhale adds its Strengh modifier (+9) to its Initiative roll 

Terrifying presence: At the start of each creatures turn that can see the Bearwhale that creature makes a DC 17 Wisdome save for be frightened for 1 min. While freighted the creature cannot approach the creature aslong as they can see it. If the Bearwhale is submerged in water the creature cannot get within 15ft of the body of water the Bearwhale entered. A creature repeats this save at the end of its turn. A creature who passes this save is immune to this effect for 24 hours.

Multiattack. The Bearwhale can make up 3 attacks in a turn.

Bite. Melee Weapon Attack: +11 to hit, reach 5 ft., one target. Hit: 21 (3d8 + 8) piercing damage. If the target is a Large or smaller creature, it must succeed on a DC 16 Dexterity saving throw or be swallowed by the Bearwhale. A swallowed creature has total cover against attacks and other effects outside the Bearwhale, and it takes 6 (2d6) acid damage at the start of each of the Bearwhale’s turns. If the Bearwhale takes 30 damage or more in a round , the Bearwhale must succeed on a DC 16 (+1 for every point of damage beyond the threshold Constitution saving throw at the end of that turn) or regurgitate all swallowed creatures, which fall prone in a space within 10 feet of the Bearwhale. If the Bearwhale dies, a swallowed creature can escape from the corpse by using 20 feet of movement, exiting prone.

Tail. Melee Weapon Attack: +11 to hit, reach 15 ft., one target. Hit: 18 (3d6 + 8) bludgeoning damage, or 37 (6d6 + 16) bludgeoning damage if the target is an object.

Claws. Melee Weapon Attack: +11 to hit, reach 15 ft., one target. Hit: 21 (4d6 + 8) slashing damage, or 40 (8d6+16) slashing damage if the target is an object.

The Bear-Whale takes up to 3 legendary actions in a round and chooses from the following: 

Crash in wake (1 action): The Bear-Whale creates large waves which crash and smash into everything around it. Creatures caught within 50ft of the Bear-Whale must make a DC 16 strength saving throw or take 4d8 bludgeoning damage and be knocked prone. 

Tail attack (1 action): The Bear-Whale makes a tail attack. 

Wail (3 actions) : The Bear-Whale makes a terrifying screeching sound that cripples the sturdiest of creatures. Each creature within 100ft of the Bear-Whale must make a DC 17 constitution saving throw or take 5d8 force damage and become Defend and silenced until the end of their turn. While Deafened and silenced creatures cannot cast spells that require verbal components. A creature who passes this save takes only half the damage.