Large aberration, lawful evil

Armor Class: 18

Hit Points: 550

Speed: 0 ft , burrow: 10 ft , can hover

STR

12 +1

DEX

14 +2

CON

18 +4

INT

19 +4

WIS

15 +2

CHA

19 +4

Saving Throws: STR (+7), DEX (+8), CON (+10), INT (+10), WIS (+8), CHA (+10)

Skills: Perception +12

Condition Immunities: Prone

Senses:

• Darkvision: 120ft.
• Passive Perception: 22

Languages: Common, Undercommon, Deep Speech

Challenge Rating: 20

Actions

• Bite. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 16 (4d6 + 2) Piercing Damage.
• Eye Rays. The beholder shoots three of the following magical Eye Rays at random (reroll duplicates), choosing one to three targets it can see within 120ft. of it. The DC for Saving Throws made against these Eye Rays is 18:
  1. Blinding Ray. The targeted creature must succeed on a Wisdom Saving Throw or be Blinded for 1 minute. The taret can repeat the Saving Throw at the end of each of its turns, ending the effect on itself on a success.
  2. Confusion Ray. The targeted creature must make an Intelligence Saving Throw. On a failed Save, the target takes 18 (4d6 + 2) Psychic Damage and cannot take Reactions until the start of its next turn. On a successful Sace, the target takes half as much Damage and may still take Reactions.
  3. Enfeeblement Ray. The targeted creature must succeed a Strength Saving Throw or have their Strength Score set to 1 for 1 minute. The creature can repeat the Saving Throw at the end of each of its turns, ending the effect on itself on a success.
  4. Frost Ray. The targeted creature must succeed on a Dexterity Saving Throw or take 20 (4d8) Cold Damage and become Slowed for 1 minute. The creature can repeat the Saving Throw at the end of each of its turns, ending the effect on itself on a success.
  5. Paralyzing Ray. The targeted creature must succeed on a 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. Poison Ray. The targeted creature must make a Constitution Saving Throw. On a failure, the target takes 40 (8d8) Poison Damage and is Poisoned. On a success, the target takes half as much Damage and is not Poisoned.
  7. Telekinetic Ray. If the target is a creature, it must succeed on a Strength Saving Throw or the beholder moves it up to 30ft. in any direction. It is Restrained by the Eye 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 300lbs. or less that isn't being worn or carried, it is moved up to 30ft. in any direction. The beholder can also exert fine control on objects within its Eye Ray, such as manipulating a simple Tool or opening a door or container.
  8. Disintegration Ray. If the target is a creature, it must succeed on a 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 Eye Ray disintegrates a 10ft. cube of it.

Reactions

• Shield Ray. The beholder causes an invisible barrier of magical force to appear and protect it. Until the start of its next turn, the beholder has a +5 bonus to AC, including against the triggering Attack, and it takes no Damage from the Spell Magic Missile.
• Temporal Shunt Ray. The beholder targets a creature it can see that makes an attack roll or starts to cast a spell. The targeted creature must succeed on a DC 18 Wisdom Saving Throw or vanish, being thrown to another point in time and causing the Attack to miss or the Spell to be wasted. At the start of its next turn, the target reappears where it was or in the closest unoccupied space. The target doesn't remember you casting the Spell or being affected by it.

Legendary Actions

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.
• Ripple Reality (2 Actions). The beholder causes minor ripples in reality. Each creature within 30ft. of it must make a DC 20 Constitution Saving Throw or be subjected to a random effect from the following list:
  1. The target has Disadvantage on all d20 Tests using Strength until the start of its next turn.
  2. The target has Disadvantage on all d20 Tests using Dexterity until the start of its next turn.
  3. The target has Disadvantage on all d20 Tests using Constitution until the start of its next turn.
  4. The target has Disadvantage on all d20 Tests using Intelligence until the start of its next turn.
  5. The target has Disadvantage on all d20 Tests using Wisdom until the start of its next turn.
  6. The target has Disadvantage on all d20 Tests using Charisma until the start of its next turn.
  7. The target is Slowed until the start of its next turn.
  8. The target suffers a -2 penalty to AC until the start of its next turn.
  9. The target can't take Reactions until the start of its next turn and on the target's next turn they can take an Action or Bonus Action, but not both. Regardless of the target’s abilities or magic items, it can’t make more than one Attack during its turn.
  10. Attacks against the target have Advantage until the start of its next turn.

Lair Actions

When fighting inside its lair, a beholder can invoke the ambient magic to take Lair Actions. On Initiative Count 20 (losing Initiative ties), the beholder can take one Lair Action to cause one of the following effects:

• A 50ft. square area of ground within 120ft. of the beholder becomes slimy; that area is difficult terrain until Initiative Count 20 on the next round.
• Walls within 120ft. of the beholder sprout grasping appendages until Initiative Count 20 on the round after next. Each creature of the beholder's choice that starts its turn within 10ft. of such a wall must succeed on a DC 15 Dexterity Saving Throw or be grappled. Escaping requires a successful DC 15 Athletics or Acrobatics Check.
• An eye opens on a solid surface within 60ft. of the beholder. One random Eye Ray of the beholder shoots from that eye at a target of the beholder's choice that it can see. The eye then closes and disappears.

The beholder can't repeat an effect until they have all been used, and it can't use the same effect two rounds in a row.