Behemoth Spirit

Amphibious. The behemoth can breathe air and water.

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

Siege Monster. The behemoth does double damage to structures and objects.

Reckless Rage. When the behemoth first attacks on its turns, it can decide to attack recklessly. Doing so gives it advantage on melee attacks using Strength during its turn, but attack rolls against it have disadvantage until its next turn.

Multiattack. The behemoth makes three Swipe attacks. It can replace one Strike with a Stomp or Swipe. It can replace two strikes with a Bite.

Strike. Melee Weapon Attack: +17 to hit, reach 10 ft., one target. Hit: 28 (4d10 + 10) bludgeoning, piercing, or slashing damage (its choice) and the target's grappled (escape DC 19). Until this grapple ends, the target's restrained. The behemoth has two armed, each of which can grapple one target.

Stomp. Melee Weapon Attack: +17 to hit, reach 10 ft., one target. Hit: 23 (2d12 + 10) bludgeoning damage. Hit or miss, all creatures within 10ft of the target make a DC 19 Dexterity save, taking 2d12 bludgeoning damage on a failure or half as much on a success. Also, structures in that area automatically take the damage, and the ground within 10ft of the target becomes difficult terrain until cleared.

Tail Swipe. The behemoth swings its tail in a 30ft radius sphere. Each creature in the area must make a DC 19 Dexterity save or take 19 (2d8+10) bludgeoning damage and be knocked prone, or no damage on a success.

Bite. Melee Weapon Attack: +17 to hit, reach 10 ft., one target. Hit: 30 (3d12 + 10) piercing damage. If the target's a Large or smaller creature grappled by the behemoth, it's swallowed, and the grapple ends. While swallowed, the creature's blinded and restrained; it has total cover against attacks and other effects outside the behemoth.

If the behemoth takes 50 damage from the creature inside, it must make a DC 25 Constitution save at the end of that turn or regurgitate all swallowed creatures, which fall prone in a space within 10ft of the behemoth. If the behemoth dies, a swallowed creature isn't restrained by it and can escape from the corpse using 15ft movement, exiting prone.

Frightful Presence. Each creature of the behemoth's choice within 120ft of it and aware of it must make a DC 19 Wisdom save or be frightened for 1 minute. A creature can repeat the save at the end of each turn, ending the effect on a success. After passing the save, it's immune to this effect for the next 24 hours.

Burst. (Recharge 6) The behemoth emits acid, frost, fire, lighting, or thunder in a 60ft cone. Creatures in that area must make a DC 19 Dexterity save. A creature takes acid, cold, fire, piercing, or thunder damage on a failure. (chooses one and keeps constant). A creature takes half damage on a success. Depending on the damage you choose, additional effects occur as below:

• Acid: 60ft cone, 18d6 acid damage. Structures and objects in the area that aren't being worn or carried automatically take the spell's damage.
• Cold: 60ft cone, 12d8 cold damage. A creature that fails its save has its speed halved until the start of the behemoth's next turn. If the creature fails by 10 or more, it's restrained for that duration. Nonmagic liquids freeze.
• Fire: 60ft cone, 12d8 fire. Creatures that fail the save ignite, taking 1d8 fire damage at the end of each turn until the fire's doused. Flammable structures and objects in the area that aren't worn or carried ignite automatically.
• Thunder: 60ft cone, 12d8 thunder damage. A creature that fails its save is pushed 10ft away from the behemoth, deafened until the start of its next turn, and knocked prone.

The behemoth has 2 legendary actions.

Aggression (Costs 1 Action). The behemoth moves up to its speed towards an enemy it sees.

Strike (Costs 1 Action). The behemoth makes one Strike attack.

Swipe or Stomp (Costs 2 Actions). The behemoth makes a Stomp or a Tail Swipe attack.