Multiattack

The voidling makes four Shadow Tendril or Necrotic Bolt attacks. If two Necrotic Bolt attacks hit one creature, the target must succeed on a DC 17 Wisdom saving throw or be frightened until the end of its next turn.

Shadow Tendril

Melee Weapon Attack: +9 to hit, reach 10 ft., one target. Hit: 8 (1d6 + 5) bludgeoning damage plus 10 (3d6) necrotic damage.

Necrotic Bolt

Ranged Spell Attack: +7 to hit, range 120 ft., one target. Hit: 17 (4d6 + 3) necrotic damage.

Shadow's Grasp (Recharge 5-6)

The voidling releases a wave of small, grasping tendrils of shadow. Each creature within 20 feet of it must make a DC 17 Dexterity saving throw. On a failure, a creature takes 49 (14d6) necrotic damage and is restrained by tendrils of shadow for 1 minute. On a success, a creature takes half the damage and isn't restrained. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.