Due to their incorporeal forms, they have resistance to Resistance to Acid, Fire, Lightning, Thunder; (NM)Bludgeoning, (NM)Piercing, and (NM)Slashing damage and are immune to Cold, Necrotic and Poison damage.

One humanoid that the ghost can see within 5 ft. of it must succeed on a Charisma saving throw or be possessed by the ghost; the ghost then disappears, and the target is incapacitated and loses control of its body. The possession lasts until the body drops to 0 hit points, the ghost ends it as a bonus action, or the ghost is turned or forced out by an effect like the dispel evil and good spell. When the possession ends, the ghost reappears in an unoccupied space within 5 ft. of the body. The target is immune to this ghost's Possession for 24 hours after succeeding on the saving throw or after the possession ends.

If it posses an inanimate object, it is able to remain in that body indefinitely until it moves onto another one or the object is shattered.

Ability score rises by CHA +2, DEX +1, WIS +1

The ghost 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 an object.

The ghost enters the Ethereal Plane from the Material Plane, or vice versa. It is visible on the Material Plane while it is in the Border Ethereal, and vice versa, yet it can't affect or be affected by anything on the other plane.

Darkvision allowed a creature to discern forms, as in normal daylight vision, but only in shades of gray. Monsters with this ability could only see in the dark up to a certain distance, typically around 20 yards (18 meters). Permanently subterranean creatures often possessed superior darkvision that allowed them to see in the dark at distances twice that far. Darkvision did not function in darkness that was magical in origin.