Beholder Yuan-ti (Polmachis)

Wild Magic Cone. Polmachis' central eye creates an area of wild magic surges, using the Wild Magic Surge table in the PHB (or the table of the DM's choice) whenever any spell is cast or moves into the area of a 60-foot-cone on anyone's turn. At the start of each of its turns, Polmachis decides which way the cone faces and whether the cone is active. He has no control over the outcome of the surge. Rather than a 1 on a D20, a 1 on a D4 is rolled to determine that a while magic surge occurs. The area works against Polmachis' own eye rays.

Bite. Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit: 11 (3d6) piercing damage.

Eye Rays. The beholder shoots two of the following magical eye rays at random (reroll duplicates), choosing to hit the same target twice or two targets it can see within 120 feet of it:

1. Charm Ray. The targeted creature must succeed on a DC 14 Wisdom saving throw or be charmed by the beholder until the end of the target's next turn, or until the beholder harms the creature.

2. Paralyzing Ray. The targeted creature must succeed on a DC 14 Constitution saving throw or be paralyzed until the end of the target's next turn. 

3. Fear Ray. The targeted creature must succeed on a DC 14 Wisdom saving throw or be frightened until the end of the target's next turn. 

4. Slowing Ray. The targeted creature must succeed on a DC 14 Dexterity saving throw. On a failed save, the target’s speed is halved until the end of the target's next turn. In addition, the creature can’t take reactions, and it can take either an action or a bonus action on its turn, not both.

5. Enervation Ray. The targeted creature must make a DC 14 Constitution saving throw, taking 28 (6d8) necrotic damage on a failed save, or half as much damage on a successful one. if the creature is undead or immune to necrotic damage, rather than being injured it gains health equal to half of the damage roll.

6. Telekinetic Ray. If the target is a creature, it must succeed on a DC 14 Strength saving throw or the beholder moves it up to 30 feet in a random direction determined by a D8 roll, with a 1 indicating north and continuing in a clockwise direction to determine the path. Every 5 feet are determined randomly until any barrier preventing further movement (including an enemy area of control) prevents it in the indicated direction. Note that a fall is not a barrier to movement. 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 a random direction determined by a D8 roll, with a 1 indicating north and continuing in a clockwise direction to determine the path. Every 5 feet are determined randomly until any barrier preventing further movement (including an enemy area of control) prevents it in the indicated 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.

7. Sleep Ray. The targeted creature must succeed on a DC 14 Wisdom saving throw or fall asleep and remain unconscious until the end of the target's next turn. The target awakens if it takes damage or another creature takes an action to wake it. This ray has no effect on constructs, undead or creatures that do not sleep (such as most elves).

8. Petrification Ray. The targeted creature must make a DC 14 Dexterity saving throw. On a failed save, the creature begins to turn to stone and is restrained. It must repeat the saving throw at the end of its next turn. On a success, the effect ends. On a failure, the creature is petrified until freed by the greater restoration spell or other magic.

9. Dissociation Ray. If the target is a creature with an intelligence above 3, it must succeed on a DC 14 Dexterity saving throw or take 35 (10d6) force damage and is stunned until the end of its next turn. If this damage would reduce the creature to 0 hit points, it instead has 1 hit point and automatically fails the save.

   If the target is a medium or smaller nonmagical object, it is disintegrated without a saving throw. If the target is a large or larger object, this ray disintegrates a 10-foot cube of it.

10. Near-Death Ray. The targeted creature must succeed on a DC 14 Dexterity saving throw or take 35 (6d10) necrotic damage. The target is stable at 1 hit point if the ray damage would reduce it to 0 hit points.

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

Eye Ray. The beholder uses one random eye ray.