Void Stone

Antimagic Cone. The Void Stone's core creates an area of antimagic, as in the antimagic field spell, in a 150-foot-cone. At the start of each of its turns, the Void Stone decides which way the cone faces and whether the cone is active. The area works against the Void Stone's own rays.

Catapult. Ranged Weapon Attack:  Choose one object weighing 1 to 5 pounds within range that isn’t being worn or carried. The object flies in a straight line up to 90 feet in a direction you choose before falling to the ground, stopping early if it impacts against a solid surface. If the object would strike a creature, that creature must make a Dexterity saving throw. On a failed save, the object strikes the target and stops moving. When the object strikes something, the object and what it strikes each take 3d8 bludgeoning damage.

Rays. The Void Stone shoots one of the following magical rays at random (reroll duplicates), choosing one target it can see within 120 feet of it:

1. Paralyzing Ray. The targeted creature must succeed on a DC 16 Constitution saving throw or be paralyzed for 1 minute. The target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.
2. Polymorph Ray. The targeted creature must make a Wisdom saving throw to avoid the effect. The new form can be any beast whose challenge rating is equal to or less than the target's. The target's game statistics, including mental ability scores, are replaced by the statistics of the chosen beast. It retains its alignment and personality.

   The target assumes the hit points of its new form. When it reverts to its normal form, the creature returns to the number of hit points it had before it transformed. If it reverts as a result of dropping to 0 hit points, any excess damage carries over to its normal form. As long as the excess damage doesn't reduce the creature's normal form to 0 hit points, it isn't knocked unconscious.

3. Slowing Ray. The targeted creature must succeed on a DC 16 Dexterity saving throw. On a failed save, the target’s speed is halved for 1 minute. In addition, the creature can’t take reactions, and it can take either an action or a bonus action on its turn, not both. The creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.
4. Telekinetic Ray. If the target is a creature, it must succeed on a DC 16 Strength saving throw or the beholder moves it up to 30 feet in any direction. It is restrained by the ray’s telekinetic grip until the start of the beholder’s next turn or until the beholder is incapacitated.
   If the target is an object weighing 300 pounds or less that isn’t being worn or carried, it is moved up to 30 feet in any direction. The beholder can also exert fine control on objects with this ray, such as manipulating a simple tool or opening a door or a container.
5. Petrification Ray. The targeted creature must make a DC 16 Dexterity saving throw. On a failed save, the creature begins to turn to stone and gaining levels of exhaustion. It must repeat the saving throw at the end of its next turn. On a failure, the target gains a level of exhaustion. On a success, nothing happens. If the target has failed six saves after six turn, the creature is petrified until freed by the greater restoration spell or other magic, otherwise the effect ends.
6. Disintegration Ray. If the target is a creature, it must succeed on a DC 16 Dexterity saving throw or take 5 (1d8) force damage at the end of each of its turns for 1 minute. If this damage reduces the creature to 0 hit points, its body becomes a pile of fine gray dust.
   If the target is a Large or smaller nonmagical object or creation of magical force, it is disintegrated without a saving throw. If the target is a Huge or larger object or creation of magical force, this ray disintegrates a 10-foot cube of it.

The Void Stone can take 3 legendary actions, using the Ray option below. It can take only one legendary action at a time and only at the end of another creature’s turn. The Void Stone regains spent legendary actions at the start of its turn.

Ray. The Void Stone uses one random eye ray.