Crag Kraken

Amphibious. The kraken can breathe air and water.

Freedom of Movement. 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.

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

Camouflage. When remaining still, the Crag Kraken can use its action to change the colour of its skin and camouflage itself, it has advantage on Stealth checks whilst doing so and so long as it remains still it is indistinguishable with large dried vines and roots or rocks. 

Multiattack. The 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 kraken, that creature is swallowed, and the grapple ends. While swallowed, the creature is blinded and restrained, it has total cover against attacks and other effects outside the kraken, and it takes 42 (12d6) acid damage at the start of each of the kraken's turns.

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

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 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.

Rockslide . The kraken rips three boulders out of the earth, each of which can strike a target the kraken can see within 120 feet of it. A target must make a DC 23 Dexterity saving throw, taking 22 (4d10) bludgeoning damage on a failed save, or half as much damage on a successful one. 60ft area around the Crag Kraken becomes difficult terrain as a rockslide forms from the action

Ink Spray (once per long rest). While above water, the crag kraken expels ink in a 60ft cone, the ink does not spread around corners, all objects and creatures within range are covered in ink, creating difficult terrain. Each creature must succeed on a DC 23 Constitution saving throw, or become blinded, in addition, all creatures that enter the area for the first time or end their turn in the area must succeed a DC 18 Dexterity saving throw or be knocked prone. Creatures can use their action on each turn to reroll their save.

EarthQuake. The Kraken uses its tentacles to rip into the earth and causes magic to flow, creating an earthquake with an area of 100ft that lasts up to (1d6) rounds but may be interrupted as the Kraken concentrates on the Earthquake as a spell, centred around the crag kraken, and all creatures, objects, and structures touching the ground are shaken, the area becomes difficult terrain, and each round all creatures, whenever they enter the area for the first time or finish their turn in that area, must make a DC 23 Dexterity saving throw or be knocked prone.  The Earthquake also has one of the following effects, determined by the GM:

• Fissures. Fissures open throughout the spell's area at the start of your next turn after you cast the spell. A total of 1d6(1d6) such fissures open in locations chosen by the GM. Each is 1d10(1d10) × 10 feet deep, 10 feet wide, and extends from one edge of the spell's area to the opposite side. A creature standing on a spot where a fissure opens must succeed on a DC 18 Dexterity saving throw or fall in. A creature that successfully saves moves with the fissure's edge as it opens.

  A fissure that opens beneath a structure causes it to automatically collapse (see below).

  Structures. The tremor deals 50 bludgeoning damage to any structure in contact with the ground in the area when the kraken begins the Earthquake and at the start of each of the crag kraken's turns until the Earthquake ends. If a structure drops to 0 hit points, it collapses and potentially damages nearby creatures. A creature within half the distance of a structure's height must make a Dexterity saving throw. On a failed save, the creature takes 5d6 (5d6) bludgeoning damage, is knocked prone and is buried in the rubble, requiring a DC 20 Strength (Athletics) check as an action to escape. The GM can adjust the DC higher or lower, depending on the nature of the rubble. On a successful save, the creature takes half as much damage and doesn't fall prone or become buried.

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 Fling. The kraken makes one tentacle attack or uses its Fling.

Earth Quake Costs 3 Actions). The kraken uses Earthquake

Rock Slide (Costs 2 actions.) The crag Kraken uses its Rock Slide ability

Ink Cloud(Costs 3 Actions). While underwater, 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 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 current disperses the cloud, which otherwise disappears at the end of the kraken's next turn.