Amphibious. The kraken can breathe air and water.

Tainted by the Far Realm. The 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. It can also move through creatures, and magical barriers.

Corrupting Touch. The kraken's tainted mind and body corrupt all those near it, any melee attack made by the kraken inflicts Madness (save DC 23 Wisdom).

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

Psychic Maelstrom. Ranged Spell Attack: +17 to hit, reach 120 ft., sphere. Hit: 23 (3d8 + 10) psychic damage. If the target is hit by this attack it must make a DC 23 Wisdom saving throw or be inflicted with Madness. While in the maelstrom, the creature is blinded and deafened, it has disadvantage on attacks to targets outside the Maelstrom, and it takes 42 (12d6) psychic damage at the start of each of each turn it remains in the Maelstrom.

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

Fling. One Large or smaller object held or creature grappled by the 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.

Cosmic Call. The kraken magically creates other tears in the space around itself, revealing the far realm. These tears in space are made by the kraken's screeching call at a random point within 120 feet of it. A target must make a DC 23 Wisdom saving throw, taking 22 (4d10) psychic damage on a failed save and being inflicted with Madness, or half as much damage on a successful one. The area around these tears become portals into the Far Realm that last for 1 minute.

As a bonus action on each of it's turns, the kraken may make 2 additional Tentacle attacks if it did not use its Psychic Maelstrom.

The kraken may use a reaction to make one tentacle attack against a target who missed a melee attack.

If the kraken is currently grappling a creature, it may may a Fling attack at any creature who missed a ranged attack.

The 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 Psychic Malestrom. The kraken makes one tentacle attack or uses its Psychic Malestrom.

Cosmic Call (Costs 2 Actions). The kraken uses Cosmic Call.

Psychic Haze (Costs 3 Actions). While tethered to the Far Realm, the kraken emits a Psychic Haze in a 60-foot radius. The haze spreads around corners, and that area is treated as difficult terrain for all creatures other than the kraken. Each creature other than the kraken that ends its turn there must succeed on a DC 23 Wisdom saving throw, taking 16 (3d10) psychic damage on a failed save, or half as much damage on a successful one. If any creature fails the save they gain disadvantage on all attack rolls and get inflicted by Madness (see: Madness Table)