Devourer Whale

Legendary Resistance (6/Day). If the Devourer Whale fails a saving throw, it can choose to succeed instead.

Echolocation. The Devourer Whale has a 120ft Blindsight, but can't use it while deafened.

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

Thick Skin. The Devourer Whale, thanks to his gargantuan size and thick skin, has a resistance to normal non magical weapons

Extremely Heavy. The Devourer Whale can survive for 3 hours on land. Every turn thereafter, the whale takes 10 bludgeoning damage for every turn it remains on land. This damage comes from its weight crushing it, so being magically lifted, being given a flying speed, or other means of the DM's discretion can prevent it. Additionally, the whale takes twice as much damage from falling, but if it falls onto a creature, that creature takes double the amount of bludgeoning damage.

Siege Monster. The Devourer Whale deals double damage to objects and structures.

Multiattack. The Devourer Whale makes one Bristle Chomp attack and three other attacks, using Jet or Fluke in any combination.

Bristle Chomp. Melee Attack Roll: +19, reach 15 ft. Hit: 36 (4d12 + 10) Piercing damage, and the target has the Grappled condition (escape DC 20). Until the grapple ends, the target has the Restrained condition and can’t teleport.

Jet (Recharge 5–6). Range Attack Roll: +19, reach 80 ft. Hit: 28 (4d8 + 10) Bludgeoning damage.

Fluke Slam. Melee Attack Roll: +19, reach 30 ft. Hit: 23 (3d8 + 10) Bludgeoning damage. If the target is a Huge or smaller creature, it has the Prone condition.

Belly Slam. Dexterity Saving Throw: DC 21, each creature and each object that isn’t being worn or carried in a 60-foot emanation. Failure: 78 (12d12) Bludgeoning damage, and the target has the Prone and Incapacitated conditions until the end of its next turn. Success: Half damage only.

Swallow. Strength Saving Throw: DC 27, one Large or smaller creature Grappled by the Devourer Whale (it can have up to six creatures swallowed at a time). Failure: The target is swallowed, and the Grappled condition ends. A swallowed creature has the Blinded and Restrained conditions and can’t teleport, it has Total Cover against attacks and other effects outside the Devourer Whale, and it takes 56 (16d6) Acid damage at the start of each of the Devourer Whale’s turns.

If the Devourer Whale takes 60 damage or more on a single turn from a creature inside it, the Devourer Whale must succeed on a DC 20 Constitution saving throw at the end of that turn or regurgitate all swallowed creatures, each of which falls in a space within 10 feet of the Devourer Whale and has the Prone condition. If the Devourer Whale dies, any swallowed creature no longer has the Restrained condition and can escape from the corpse using 20 feet of movement, exiting Prone.

Legendary Action Uses: 3. Immediately after another creature’s turn, the Devourer Whale can expend a use to take one of the following actions. The Devourer Whale regains all expended uses at the start of each of its turns.

Submerged Menace. The Devourer Whale moves up to half its Speed, and it makes one Bristle Chomp or Fluke attack.

Ocean-Current Movement. The Devourer Whale moves up to its Speed. At the end of this movement, the Devourer Whale creates an instantaneous oceanic current in a 80-foot long and 15-foot wide cilindrical Emanation originating from itself. Creatures in that area lose Concentration and, if Medium or smaller, have the Prone condition. The Devourer Whale can’t take this action again until the start of its next turn.