Astral Kraken

Maddening Visage. Upon seeing the astral kraken for the first time, any creature with an intelligence greater than 5 must make a Wisdom Saving Throw (DC10). On a failed save, the creature suffers from Short Term Madness for 5 (1d10) minutes or until the effect has been cured. 

Astral Entity. The astral kraken can't leave the Astral Plane, nor can it be banished or otherwise transported out of the Astral Plane.

Demiplanar Stomach. Any creature or object that the astral kraken swallows is transported to a demiplane that can be entered by no other means except a wish spell. A creature can leave the demiplane only by using magic that enables planar travel, such as the plane shift spell. The demiplane resembles a whirling astral vortex roughly 100 feet in diameter with a ceiling 1,000 feet high. Like a stomach, it contains the remains of the astral kraken's past meals. The astral kraken can't be harmed from within the demiplane. If the astral kraken dies, the demiplane disappears, and everything inside it appears around the corpse. The demiplane is otherwise indestructible.

Freedom of Movement. The astral kraken ignores difficult terrain, and magical effects can't reduce its speed or cause it to be restrained. It can spend 5 feet of movement to escape from nonmagical restraints or being grappled.

Magic Weapons. An astral kraken's weapon attacks are magical.

Sever Silver Cord. lf the astral kraken scores a critical hit against a creature traveling through the Astral Plane by means of the astral projection spell, the kraken can cut the target's silver cord instead of dealing damage.

Siege Monster. The astral kraken deals double damage to objects and structures.

Voidborn. The astral kraken has its own gravity, and does not require air to live.

Multiattack. The astral kraken makes three tentacle attacks, each of which it can replace with one use of Fling.

Bite. Melee Weapon Attack: +17 to hit, reach 5 ft., one target. Hit: 23 (3d8 + 10) piercing damage. If the target is a Large or smaller creature grappled by the astral kraken, that creature is swallowed, and the grapple ends. While swallowed, it has total cover against attacks and other effects outside the astral kraken, and it takes 42 (12d6) psychic damage at the start of each of the astral kraken's turns.

If the astral kraken takes 50 damage or more on a single turn, the kraken must succeed on a DC 25 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 kraken. If the astral kraken dies, a swallowed creature is no longer restrained by it and can escape from the corpse using 15 feet of movement, exiting prone.

Extract Brain. Melee Weapon Attack: +17 to hit, reach 5 ft., one incapacitated humanoid grappled by the astral kraken. Hit: The target takes 55 (10d10) piercing damage. If this damage reduces the target to 0 hit points, the astral kraken kills the target by extracting and devouring its brain.

Tentacle. Melee Weapon Attack: +17 to hit, reach 30 ft., one target. Hit: 20 (3d6 + 10) bludgeoning damage, and the target is grappled (escape DC 18). Until this grapple ends, the target is restrained. The astral kraken has ten tentacles, each of which can grapple one target.

Fling. One Large or smaller object held or creature grappled by the astral kraken is thrown up to 60 feet in a random direction and knocked prone. If a thrown target strikes a solid surface, the target takes 3 (1d6) bludgeoning damage for every 10 feet it was thrown. If the target is thrown at another creature, that creature must succeed on a DC 18 Dexterity saving throw or take the same damage and be knocked prone.

Lightning Storm. The astral kraken magically creates three bolts of lightning, each of which can strike a target the astral kraken can see within 120 feet of it. A target must make a DC 23 Dexterity saving throw, taking 22 (4d10) lightning damage on a failed save, or half as much damage on a successful one.

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

Tentacle Attack or Fling. The astral kraken makes one tentacle attack or uses its Fling.

Lightning Storm (Costs 2 Actions). The astral kraken uses Lightning Storm.

Nebula of Confusion (Costs 3 Actions). While in the astral sea, the kraken expels an ink cloud in a 60-foot radius. The cloud spreads around corners, and that area is heavily obscured to creatures other than the astral kraken. Each creature other than the kraken that ends its turn there must succeed on a DC 23 Constitution saving throw, taking 16 (3d10) poison damage on a failed save, or half as much damage on a successful one. A strong gust of wind disperses the cloud, which otherwise disappears at the end of the kraken's next turn.

Psychic Projection (Costs 3 Actions). Each creature within 60 feet of the astral kraken must make a DC 19 Wisdom saving throw, taking 15 (2d10 + 4) psychic damage on a failed save, or half as much damage on a successful one.