Astral Oar

Legendary Resistance (3/Day). If the Astral Oar fails a saving throw, it can choose to succeed instead.

Multiattack. The Astral Oar can use its Alien Mind. It then makes three attacks: one with its bite and two with its claws.

Bite. Melee Weapon Attack: +11 to hit, reach 10 ft., one target. Hit: 17 (2d10 + 6) piercing damage.

Claw. Melee Weapon Attack: +11 to hit, reach 5 ft., one target. Hit: 13 (2d6 + 6) slashing damage.

Tail. Melee Weapon Attack: +11 to hit, reach 15 ft., one target. Hit: 15 (2d8 + 6) bludgeoning damage.

Tentacles. Melee Weapon Attack: +13 to hit, reach 15 ft., one target. Hit: 21 (3d8 + 8) bludgeoning damage plus 13 (3d8) psychic damage. If the target is a Large or smaller creature, it must succeed on a DC 18 Strength saving throw or be swallowed by the Astral Oar. A swallowed creature is Blinded and Restrained, it has total cover against attacks and other effects outside the Astral Oar, and it takes 35 (10d6) acid damage at the start of each of the Astral Oar’s turns.

If the Astral oar takes 30 damage or more on a single turn from a creature inside it, the Astral oar must succeed on a DC 18 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 Astral oar. If the Astral oar dies, a swallowed creature is no longer restrained by it and can escape from the corpse by using 20 feet of movement, exiting prone.

Acid Breath (Recharge 5–6). The Astral Oar exhales acid in a 60-foot cone. Each creature in that area must make a DC 18 Dexterity saving throw, taking 35 (10d6) acid damage on a failed save, or half as much damage on a successful one.

Alien Mind. Each creature of the astral oar's choice that is within 120 feet of the astral oar and aware of it must succeed on a DC 18 Wisdom saving throw or become frightened for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a creature's saving throw is successful or the effect ends for it, the creature is immune to the Astral Oar's Alien Mind for the next 24 hours.

The astral oar 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 astral oar regains spent legendary actions at the start of its turn.

Detect. The Astral Oar makes a Wisdom (Perception) check.

Tail Attack. The Astral Oar makes a tail attack.

Psionic Scream (Costs 2 Actions). The astral oar projects its pain through the mental space around it. Each creature within 10 feet of the astral oar must succeed on a DC 19 wisdom saving throw or take (3d6 + 6) Psychic damage and be knocked prone. The Astral Oar then does not provoke opportunity attacks until the end of its next turn.