Beholder Overseer

Magic Resistance. The beholder has advantage on saving throws against spells and other magical effects.

Innate Spellcasting. The overseer’s innate spellcasting ability is Intelligence (spell save DC 20). It can innately cast the following spells, requiring no components:

At will: detect thoughts, mage hand, message
3/day each: mass charm, mass suggestion, major creation, globe of invulnerability, dispel magic, counterspell, dominate monster
1/day each: imprisonment, time stop

Bite. Melee Weapon Attack: +20 to hit, reach 5 ft., one target. Hit: 34 (4d12+8) piercing damage. Any attack roll that exceeds the number needed by 5 or more means the overseer has swallowed its target whole, unless the target is bigger than it.
While inside of its belly, the swallowed creature takes 19 (3d12) acid damage and 19 (3d12) bludgeoning damage at the beginning of each of the overseer’s turns. A creature inside the overseer, a creature is considered restrained.

Eye Rays. The Overseer shoots six of the following magical eye rays at random (reroll duplicates), choosing one to six targets it can see within 120 feet of it:

1. Cold Ray. The targeted creature must must succeed on a DC 20 Dexterity saving throw, taking 36 (8d8) fire damage on a failed save, or half as much damage on a successful one.
2. Fire Ray. The targeted creature must succeed on a DC 20 Dexterity saving throw, taking 36 (8d8) fire damage on a failed save, or half as much damage on a successful one.
3. Confusion Ray. The target must succeed on a DC 20 Wisdom saving throw, or it can’t take reactions until the end of its next turn. On its turn, the target can’t move, and it uses its action to make a melee or ranged attack against a randomly determined creature within range. If the target can’t attack, it does nothing on its turn.
4. Dispel Ray. Any spell of 3rd level or lower on the target ends. For each spell of 4th level or higher on the target, the beholder makes a Charisma check. The DC equals 10 + the spell’s level. On a successful check, the spell ends.
5. Paralyzing Ray. The targeted creature must succeed on a DC 20 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.
6. Fear Ray. The targeted creature must succeed on a DC 20 Wisdom saving throw or be frightened 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.
7. Lightning Ray. The targeted creature must succeed on a DC 20 Dexterity saving throw, taking 36 (8d8) lightning damage on a failed save, or half as much damage on a successful one.
8. Enervation Ray. The targeted creature must make a DC 20 Constitution saving throw, taking 36 (8d8) necrotic damage on a failed save, or half as much damage on a successful one.
9. Telekinetic Ray. If the target is a creature, it must succeed on a DC 20 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.
10. Domination Ray. The targeted creature must succeed on a DC 20 Wisdom saving throw or be charmed by the beholder until the start of the beholder’s next turn. This charm works like the Dominate Monster spell.
11. Petrification Ray. The targeted creature must make a DC 20 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.
12. Disintegration Ray. If the target is a creature, it must succeed on a DC 20 Dexterity saving throw or take 45 (10d8) force damage. 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.
13. Death Ray. The targeted creature must succeed on a DC 20 Dexterity saving throw or take 55 (10d10) necrotic damage. The target dies if the ray reduces 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.