Antimagic Cone. The beholder’s central eye creates an area of antimagic, as in the antimagic field spell, in a 20-meter cone. At the start of each of its turns, the beholder decides which way the cone faces and whether the cone is active. The area works against the beholder’s own eye rays.
Spellcasting. The beholder uses Psionics (Int) to cast spells (spell save DC 16, +8 to hit with spell attacks). It has 12 mana, a mana limit of 2, regains all expended mana when it finishes a long rest and regains half its total mana when it finishes a short rest. It knows the following spells:
2 mana: stasis
Bite (1/turn). Melee Weapon Attack: +5 to hit, reach 1 m. Hit: 14 (4d6) piercing damage.
Eye Rays (1/turn). The beholder shoots three of the following magical eye rays at random (reroll duplicates), choosing one to three targets it can see within 20 meters of it:
Charm Ray. The targeted creature must succeed on a DC 16 Will saving throw or be charmed by the beholder for 1 hour, or until the beholder harms the creature.
Paralyzing Ray. The targeted creature must succeed on a DC 16 Fortitude 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.
Fear Ray. The targeted creature must succeed on a DC 16 Will 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.
Slowing Ray. The targeted creature must succeed on a DC 16 Will saving throw. On a failed save, the creature is staggered and its speed is halved 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.
Enervation Ray. The targeted creature must make a DC 16 Fortitude saving throw, taking 36 (8d8) necrotic damage on a failed save, or half as much damage on a successful one.
Telekinetic Ray. If the target is a creature, it must succeed on a DC 16 Reflex saving throw or the beholder moves it up to 5 meters 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 150 kilos or less that isn’t being worn or carried, it is moved up to 5 meters 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.
Sleep Ray. The targeted creature must succeed on a DC 16 Will saving throw or fall asleep and remain unconscious for 1 minute. The target awakens if it takes damage or another creature uses an action to wake it. This ray has no effect on constructs and undead.
Petrification Ray. The targeted creature must make a DC 16 Fortitude 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 restoration spell augmented to greater restoration or other magic.
Disintegration Ray. If the target is a creature, it must succeed on a DC 16 Reflex saving throw or take 45 (10d8) force damage. If this damage reduces the creature to 0 health, 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 2-meter cube of it.
Death Ray. The targeted creature must succeed on a DC 16 Reflex saving throw or take 55 (10d10) necrotic damage. The target dies if the ray reduces it to 0 health.
Legendary Actions (3)
Only one legendary option can be used 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.
On initiative count 20 (losing initiative ties), the beholder takes a lair action to cause one of the following effects; the same effect can’t be used two rounds in a row:
A 10-meter square area of ground within 20 meters of the beholder becomes slimy; that area is difficult terrain until initiative count 20 on the next round.
Walls within 20 meters 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 2 meters of such a wall must succeed on a DC 16 Reflex saving throw or be grappled. Escaping requires a successful DC 16 Acrobatics or Brawn check.
An eye opens on a solid surface within 10 meters 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 region containing the beholder's lair is warped by the beholder’s magic, which creates one or more of the following effects:
Creatures within 2 kilometers of the beholder’s lair sometimes feel as if they’re being watched when they aren’t.
When the beholder sleeps, minor warps in reality occur within 2 kilometers of its lair and then vanish 24 hours later. Marks on cave walls might change subtly, an eerie trinket might appear where none existed before, harmless slime might coat a statue, and so on. These effects apply only to natural surfaces and to nonmagical objects that aren’t on anyone’s person.
If the beholder dies, these effects fade over the course of 1d10 days.
No concoctions, maneuvers, or spells
All creatures in this system should have maneuvers or spells. You should add some maneuvers or spells to this creature. If you do so, please make a suggestion on github so I can finish adding maneuvers and spells to all creatures via https://github.com/mlenser/kryx-rpg-issues/issues/9