Vengeful Ghost

Melee Weapon Attack: +5 to hit reach 5 ft. one target. Hit: 17 (4d6 + 3) necrotic damage. If the target is frightened it is magically aged 1d4 x 10 years. The aging effect can be reversed with a greater restoration spell.

The ghost magically shifts from the Material Plane to the Ethereal Plane or vice versa. If it wishes it can be visible to creatures on one plane while on the other.

Each non-undead creature within 60 feet and on the same plane of existence that can see the ghost makes a DC 13 Wisdom saving throw. On a failure a creature is frightened for 1 minute. A frightened creature repeats the saving throw at the end of each of its turns ending the effect on itself on a success. If a creatures saving throw is successful or the effect ends for it it is immune to this ghosts Horrifying Visage for 24 hours.

One humanoid within 5 feet makes a DC 13 Charisma saving throw. On a failure it is possessed by the ghost. The possessed creature is unconscious. The ghost enters the creatures body and takes control of it. The ghost can be targeted only by effects that turn undead and it retains its Intelligence Wisdom and Charisma. It grants its host body immunity to being charmed and frightened. It otherwise uses the possessed creatures statistics and actions instead of its own. It doesnt gain access to the creatures memories but does gain access to proficiencies nonmagical class features and traits and nonmagical actions. It can't use limited-used abilities or class traits that require spending a resource. The possession ends after 24 hours when the body drops to 0 hit points when the ghost ends it as a bonus action or when the ghost is turned or affected by dispel evil and good or a similar effect. Additionally the possessed creature repeats its saving throw whenever it takes damage. When the possession ends the ghost reappears in a space within 5 feet of the body. A creature is immune to this ghosts Possession for 24 hours after succeeding on its saving throw or after the possession ends.