Void Phantom

Ethereal Sight. The void phantom can see 60 feet into the Ethereal Plane when it is on the Material Plane, and vice versa.

Incorporeal Movement. The void phantom can move through other creatures and objects as if they were difficult terrain. It takes 5 (1d10) force damage if it ends its turn inside a creature or an object.

Ghostly Form. The void phantom can pass through solid objects such as walls or floors, but it cannot end its turn inside one.

Void Form. The void phantom can become ethereal for up to 1 minute, making it immune to all damage except force and radiant while in this state. It can revert to its corporeal form as a bonus action. Once used, this ability can't be used again until the phantom finishes a long rest.

Multiattack. The void phantom makes two Void Touch attacks.

Void Touch. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 15 (3d6 + 4) necrotic damage. The target must succeed on a DC 15 Constitution saving throw or have its maximum hit points reduced by the amount of necrotic damage taken. This reduction lasts until the creature finishes a long rest.

Void Pulse (Recharge 5-6). The void phantom releases a pulse of dark energy in a 20-foot radius around it. Each creature in the area must make a DC 15 Dexterity saving throw or take 22 (4d10) necrotic damage, or half as much on a successful save. Creatures that fail the saving throw also have disadvantage on their next attack roll or saving throw within the next 1 minute.

Gravitational Pull (Recharge 6). The void phantom creates a gravitational anomaly that pulls creatures toward it. Each creature within 20 feet of the phantom must succeed on a DC 15 Strength saving throw or be pulled 15 feet closer to the phantom. A creature that fails by 5 or more is knocked prone.

Ethereal Jaunt (Recharge 4-6). When the void phantom is hit by an attack, it can use its reaction to become ethereal and move up to 30 feet away from the attacker without provoking opportunity attacks.

The void phantom can take 2 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature's turn. The void phantom regains spent legendary actions at the start of its turn.

Attack. The void phantom makes one Void Touch attack.

Phase Shift. The void phantom becomes incorporeal for a brief moment, allowing it to move up to half its movement speed without provoking opportunity attacks.

Mind Distortion (Costs 2 Actions). The void phantom causes a creature within 30 feet to make a DC 16 Wisdom saving throw. On a failed save, the target suffers from the Confusion spell's effects 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.