Uth Duna

Amphibious. The uth duna can breathe air and water.

Damage Transfer. While the uth duna's body is covered by its Water Veil, it takes only half the damage dealt to it, and the Water Veil takes the other half.

Legendary Resistance (2/Day). If the uth duna fails a saving throw, it can choose to succeed instead.

Standing Leap. The uth duna's long jump is up to 40 feet and its high jump is up to 20 feet, without a running start. In addition, the uth duna does not provoke opportunity attacks while moving with a jump.

Tidebreaker. While the uth duna is covered by its Water Veil and is in at least 1 foot of water, its melee weapon attacks create surging waves in a 15-foot cone, and its other actions (including legendary actions except Riptide) create surging waves in a 15-foot radius around it. Each creature in the area is pushed 10 feet away from the uth duna and must succeed on a DC 18 Strength saving throw or be knocked prone.

Status: Water blight.  A creature afflicted by waterblight has its stamina drained. On the creatures turn, it can use either an Action or a Bonus Action, not both.

Multiattack The uth duna makes two Claw attacks.

Bite. Melee Weapon Attack: +10 to hit, reach 10 ft., one target. Hit: 24 (4d8 + 6) piercing damage. If the target is a creature, it must succeed on a DC 19 Constitution saving throw or be afflicted with waterblight for 1 minute. A creature can repeat its saving throw at the end of each of its turns, ending the effect on a success.

Claw. Melee Weapon Attack: +10 to hit, reach 15 ft., one target. Hit: 13 (2d6 + 6) slashing damage. If the target is a creature, it must succeed on a DC 19 Constitution saving throw or be afflicted with waterblight for 1 minute. A creature can repeat its saving throw at the end of each of its turns, ending the effect on a success.

Tail. Melee Weapon Attack: +10 to hit, reach 20 ft., one target. Hit: 22 (3d10 + 6) bludgeoning damage. If the target is a creature, it must succeed on a DC 19 Constitution saving throw or be afflicted with waterblight for 1 minute. A creature can repeat its saving throw at the end of each of its turns, ending the effect on a success.

Crush. The uth duna stands on its hind legs, then slams its body in an area within 20 feet of its location that contains one or more other creatures. Each of those creatures must succeed on a DC 18 Strength or Dexterity saving throw (target's choice) or be knocked prone and take 28 (4d10 + 6) bludgeoning damage. On a successful save, the creature takes only half the damage, isn't knocked prone, and is pushed 5 feet out of the uth duna's space into an unoccupied space of the creature's choice. If no unoccupied space is within range, the creature instead falls prone in the uth duna's space.

Thrash (Recharge 5-6). The uth duna spins in place, lashing out with its body and tail. Each creature within 15 feet of the uth duna must make a DC 18 Dexterity saving throw. On a failed save, the creature takes 33 (6d 10) bludgeoning damage and be knocked prone. On a successful save, the creature takes half as much damage and isn't knocked prone

Tsunami (Recharge 6). If the uth duna is swimming it performs a breach, creating a wave that is up to 100 feet long, 20 feet high, and 10 feet thick. When the wave appears, each creature within its area must make a DC 18 Strength saving throw. On a failed save, a creature takes 33 (6d10) bludgeoning damage, or half as much damage on a successful save. At the start of each of uth duna's subsequent turns, the wave moves 50 feet away from it, Any Large or smaller creature inside the wave or whose space the wave enters when it moves must succeed on a DC 18 Strength saving throw or take 27 (5d10) bludgeoning damage. A creature can take this damage only once per round. At the end of the turn, the waves's height is reduced by 5 feet, and the damage creatures take from the wave on subsequent rounds is reduced by 5 (1d10). The wave disappears when it reaches O feet in height.

Water Veil (Recharge 5-6). The uth duna coats its body in a veil of water and its secretions it gain an plus +3 to it AC while the veil is active it can be attacked and destroyed (AC 16; hp 52 (3d20 + 21)); immunity to acid, poison, and psychic damage). The uth duna's Water Veil can't recharge until after it’s been destroyed.

”The uth duna can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature's turn. The uth duna regains spent legendary actions at the start of its turn.”

Riptide. Each creature within 30-feet of the uth duna must succeed on a DC 18 Strength saving throw or be pulled into the closest unoccupied space to uth duna.

Slither (Costs 2 Actions). The uth duna moves up to its speed on its belly. During this move, it can move through the spaces of other creatures without provoking opportunity attacks. Each creature the uth duna moves through must succeed on a DC 18 Dexterity saving throw or take 17 (3d8 + 4) bludgeoning damage and be knocked prone on a failed save, or half as much damage, but is still knocked prone on a successful one.

Breach (Costs 3 Actions). The uth duna jumps up to half its speed speed. During this jump, it can move through and land in the spaces of other creatures without provoking opportunity attacks. Each creature the uth duna moves through or lands on must succeed on a DC 18 Strength or Dexterity saving throw (target's choice) or be knocked prone and take 13 (3d8) bludgeoning damage. On a successful save, the creature takes only half the damage, isn't knocked prone. If it succeed on the save and is in a space uth duna lands in, it is also pushed 5 feet out of the uth duna's space into an unoccupied space of the creature's choice. If no unoccupied space is within range, the creature instead falls prone in the uth duna's space At the end of the next creature's turn, the uth duna repeats the breach into a different space.