Fed by Darkness. A Voidling in magical darkness at the start of its turn heals 5 hit points.

Reduced Void. A Voidling is tiny or small of it's choosing out of combat. It's growth into a medium monster is nearly instant and can not be stopped by material means. If it grows inside of an object, it takes (1d10) force damage each turn until it escapes combat or escapes from it's location.

Dark Void Appearance. A Voidling in complete darkness is considered invisible to creatures that rely on normal vision or darkvision.

Incomprehensible Void Origins. Each creature that is within 60 feet of the aberration and aware of it must succeed on a DC 14 Wisdom saving throw or become stunned for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success and becoming immune to this effect for the next 24 hours.

Death by Daylight. In the presence of light, such as daylight, radiance magic, or fire, a Void-Borne begins to decay, taking 2d6 radiant damage when it starts its turn in sunlight or within 15 feet of the source of light.

Incorporeal Movement. The Voidling can move through objects as if they were difficult terrain. It takes 5 (1d10) force damage if it ends its turn inside an object.

Multiattack. The Voidling makes a single Eye Ray attack and either two tentacle attacks, or a Lashing Void and Devouring Void attack.

Chaotic Tentacles. Ethereal shadowy tentacles seem to form out of thin air and lash out at a target. Melee Weapon Attack: +6 to hit, reach 10ft., one target. Hit: 12 (2d6 + 5) bludgeoning damage, and the target is grappled (escape DC 14). Until this grapple ends, the target is restrained. The Voidling has 9 tentacles, each of which can grapple one target.

Devouring Void. The Voidling starts to devour the target. Targets only a grappled target by one of it's tentacles. The target must make a Wisdom save of DC16 and a Constitution save of DC14. The Voidling starts sucking the life out of the target, they feel their life force and energy draining into the void. Takes 12 (4d6) psychic damage. Doing this will start to drag the target into the void, they  9 (3d6) force damage or half of both their respective successful saving throws.

Voids Embrace (Recharge 5–6). To consume, the creature must open it's reality defying maw. Each creature within 10 feet of the Voidling, except other void creatures, must succeed on a DC 16 Dexterity saving throw or take 12 (3d8) force damage and 8 (2d8) cold damage.

Void Rays. A Voidling shoots one of the following magical eye ray attacks at random, choosing one target 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 for 1 minute, 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 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.
3. Fear Ray. The targeted creature must succeed on a DC 16 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.
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 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.
5. Enervation Ray. The targeted creature must make a DC 14 Constitution saving throw, taking 8 (2d8) necrotic damage on a failed save, or half as much damage on a successful one.
6. Sleep Ray. The targeted creature must succeed on a DC 14 Wisdom saving throw or fall asleep and remain unconscious for 1 minute. The target awakens if it takes damage or another creature takes an action to wake it. This ray has no effect on constructs and undead.
7. Disintegration Ray. If the target is a creature, it must succeed on a DC 14 Dexterity saving throw or take 12 (3d8) 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.
8. Death Ray. The targeted creature must succeed on a DC 12 Dexterity saving throw or take 10 (2d10) necrotic damage. The target dies if the ray reduces it to 0 hit points. Only affects the living.
9. Stasis Ray. The targeted creature must succeed on a DC 14 Wisdom saving throw or fall asleep and remain unconscious for 1 minute. The target also gains 10 temporary hit points. The target awakens if it takes damage.
10. Phasing Ray. The targeted creature must succeed on a DC 15 Dexterity saving throw. On a failed save, the target is stunned until the end of its next turn. While stunned, the creature is invisible.
11. Insanity Ray. The targeted creature must succeed on a DC 14 Wisdom saving throw or be affected by a Crown of Madness spell 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.
12. Void Ray. The target must make a DC 18 Dexterity saving throw, taking 5 (1d10) force damage and 10 (2d10) cold damage on a failed save, or half as much damage on a successful one.

A Voidling is a embodiment of chaos and thus when it reacts it does so with it's primal instincts. 

Chaotic Void. When targeted by a magic attack, the Voidling can do a spell saving throw. If succeeds, the attack is sent to another person within sight. If fails, it takes the damage but then uses Chaotic Travel.

Chaotic Travel. When Voidling is hit by an attack, it teleports 10 feet in a random direction.

The Voidling can take 1 legendary actions, using the Void Ray or Void Stride. 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.

Void Ray. The Voidling uses one random void ray. Use D12 to determine.

Void Stride. As a bonus action, the Voidling can step into the Far Realm and magically appear in an unoccupied space within 60 feet. This does not provoke an opportunity attack.