Ceadeus

Amphibious. The Ceadeus can breathe air and water.

Multiattack. The Ceadeus makes three attacks: one with its bite and two with its claws. It can make one tail attack in place of its two claw attacks.

Bite. Melee Weapon Attack: +13 to hit, reach 15 ft., one target. Hit: 26 (3d12 + 7) piercing damage.

Claw. Melee Weapon Attack: +13 to hit, reach 10 ft., one target. Hit: 16 (2d8 + 7) slashing damage.

Tail. Melee Weapon Attack: +13 to hit, reach 15 ft., one target. Hit: 26 (3d12 + 7) bludgeoning damage. If the target is a creature, it must succeed on a DC 20 Strength saving throw or be pushed up to 10 feet away from the dragon turtle and knocked prone.

Water jet (Recharge 5–6). The Ceadeus exhales water in a 60-foot cone. Each creature in that area must make a DC 18 Constitution saving throw, taking 52 (15d6) force damage on a failed save, or half as much damage on a successful one. Being underwater doesn't grant resistance against this damage.

Gore. Melee Weapon Attack: +6 to hit, reach 15 ft., one target. Hit: 13 (2d20 + 4) piercing damage

Ceadeus rarely reacts but when it does it will bite.

Abyssal Whale's Vortex. The whale draws water towards its mouth and uses a stronger bite. hit:26(3d20+10)

Divine Interventional Earthquake. Ceadeus bangs it's head against the sea floor and rocks and debris. Target: all party members (2d12+3)