Amphibious Undead. The Krakken does not need to breathe.

Freedom of Movement. The Krakken ignores difficult terrain, and magical effects can't reduce its speed or cause it to be restrained.

Multiattack. The Krakken makes two tentacle attacks, each of which it can replace with one use of Fling.

Bite. Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit:  (2d4 + 4) piercing damage. 

Tentacle. Melee Weapon Attack: +5 to hit, reach 30 ft., one target. Hit:  (2d6 + 5) bludgeoning damage, and the target is grappled (escape DC 13). Until this grapple ends, the target is restrained. The Krakken has 12 tentacles, 2 of which can grapple one target each.

Fling. One Large or smaller object held or creature grappled by the Krakken 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 15 Dexterity saving throw or take the same damage and be knocked prone.

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

Ink Cloud (Costs 2 Actions). While underwater, the Krakken 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 Krakken. A strong current disperses the cloud, which otherwise disappears at the end of the Krakken's next turn.