Behemoth (Evolve)

False Appearance. If the behemoth is motionless and curled in it's rolling stone form (See Bonus Action) at the start of combat, it has Advantage on its initiative roll. Moreover, if a creature hasn't observed the behemoth move or act, that creature must succeed on a DC 18 Intelligence (Investigation) check to discern that the behemoth isn't an ordinary Huge pile of volcanic rock.

Voracious Hunger. If the behemoth eats a Small or larger creature over the course of a minute, it regains 22 (2d12 + 9) Hit Points.

Legendary Resistance (1/Day). If the behemoth fails a saving throw, it can choose to succeed instead.

Multiattack. The behemoth makes two Slam attacks. It can replace one attack with a use of Fissures, Lava Spit, or Spellcasting if available.

Slam. Melee Weapon Attack : +14 to hit, reach 10 ft., 1 target. Hit : 21 (3d8 + 8) Bludgeoning damage.

Fissures. Dexterity saving throw, DC 22, each creature on the ground in a 60-foot cone. Failure : 10 (3d6) Bludgeoning damage and the target has the Prone condition. Success : Half damage only. Success or Failure : The ground in that area becomes difficult terrain for Large or smaller creatures until cleared. Each 5-foot-square portion of the area requires at least 1 minute to clear by hand.

Lava Spit (Recharge 5-6). Dexterity saving throw, DC 22, each creature in a 10 feet-radius sphere centered on a point the behemoth can see within 60 feet. Failure : 21 (6d6) Fire damage. Success : Half damage. Success or Failure : Until the end of the behemoth's next turn, the area is difficult terrain for Large or smaller creatures, and it keeps burning for 1 minute. When a creature enters this area for the first time on a turn or starts its turn there, it must repeat it's saving throw as described above.

Spellcasting (Recharge 5-6). The behemoth casts Wall of Stone, requiring no Material components and using Constitution as the spellcasting ability (spell save DC 22).

Rolling Stone. The behemoth rolls up into a ball to move at a faster pace, or unrolls. In this form, it's AC increases by 4 (for a total of 26), its speed is doubled, it has the Blinded condition, and the only actions it can take are the Dash and Hide actions.

Additionally in this form, the behemoth can move throught the space of Large or smaller creatures, when it does so, the creature is targeted once by the following effect. Strength or Dexterity Saving Throw (creature's choice), DC 22, Failure : 9 (2d8) Bludgeoning damage and the target is knocked Prone. Success : Half damage only.

Sticky Tongue. Dexterity Saving Throw, DC 22, one Large or smaller creature can see within 60 feet. Failure : The target is pulled up to 30 feet closer to the behemoth.

Legendary Action Uses : 1. Immediately after another creature's turn, the behemoth can expend a use to take one of the following actions. The behemoth regains all expended uses at the start of each of its turns.

Hunt. The behemoth moves up to half its Speed without provoking Oppotunity attacks, and it makes one Slam attack.

Hunt. The behemoth makes a Wisdom (Survival or Perception) check.