Dark Abyssal Aura: The Voidshatter Behemoth emits an aura of darkness in a 60-foot radius. All plants within this area wither and die, and animals are frightened and have disadvantage on saving throws against fear. Spellcasters within the area have disadvantage on spell attack rolls and must succeed on a DC 19 Constitution saving throw to maintain concentration on spells.

Voidquake Stomp: The Voidshatter Behemoth stomps the ground, creating a shockwave. All creatures within a 60-foot radius must make a DC 20 Strength saving throw or be knocked prone and take 6d10 force damage. Structures in the area must make a DC 20 Dexterity saving throw or suffer damage based on their construction.

Magic Resistance: The Voidshatter Behemoth has advantage on saving throws against spells and other magical effects.

Multiattack: The Voidshatter Behemoth can make two Dark Matter Eruption attacks or use Singularity Pull once.

Tentacle Strike: Melee Weapon Attack: +16 to hit, reach 20 ft., one target. Hit: 48 (6d10 + 9) bludgeoning damage and the target is grappled (escape DC 20).

Dark Matter Eruption: Ranged Spell Attack: +9 to hit, range 120 ft., one target. Hit: 25 (6d6 + 5) force damage. The target and all creatures within 20 feet of it must make a DC 19 Dexterity saving throw or take an additional 5d6 necrotic damage from the explosion.

Singularity Pull: The Voidshatter Behemoth creates a 30-foot radius zone that draws in creatures and objects. All creatures within the zone must make a DC 20 Strength saving throw or be pulled 20 feet toward the center. Any objects in the zone are moved to the center of the effect. After the pull, the area becomes difficult terrain for 1d6 rounds.

Reactive Void Shield (Recharge 5-6): The Voidshatter Behemoth can activate a protective barrier of void energy. Until the start of its next turn, it has resistance to all damage.

1. Void Shield: When the Voidshatter Behemoth is hit by a ranged spell attack, it can use its Void Shield as a reaction to create a protective barrier of void energy. Until the start of its next turn, it has resistance to the triggering spell's damage.

2. Absorb Essence (Recharge 6): When a creature within 30 feet of the Voidshatter Behemoth drops to 0 hit points, it can use its Absorb Essence reaction. The creature's life essence is absorbed by the Voidshatter Behemoth, restoring 50 hit points to the behemoth. The absorbed essence is lost, and the creature cannot be resurrected.

Legendary Resistance (3/Day): If the Voidshatter Behemoth fails a saving throw, it can choose to succeed instead.

The Voidshatter Behemoth 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 Voidshatter Behemoth regains spent legendary actions at the start of its turn.

Voidshatter Slam: The Voidshatter Behemoth makes a Tentacle Strike attack.

Voidstep: The Voidshatter Behemoth teleports up to 60 feet to an unoccupied space it can see.

Voidswirl (Costs 2 Actions): The Voidshatter Behemoth creates a vortex of dark energy in a 30-foot radius centered on a point it can see within 120 feet. All creatures in that area must make a DC 20 Strength saving throw or be teleported to a random unoccupied space within 60 feet of the vortex. This effect cannot teleport a creature into solid objects or dangerous terrain.