Bhut

A bhut is the spirit of a creature killed violently that never received proper funeral rites. As such, it is unable to move on and plagues the living in its hatred. A bhut is likely to observe others while in the guise of a beast, only to assume its true form when it encounters a lone humanoid.

Foul Shapechanger. The area around a bhut is blighted and creatures which come into contact with the spirit often catch disease. It can assume the form of any common beast and does so to move about without drawing attention. A bhut can also possess a corpse, including its own, to confront its killers or their descendents. It prefers to initiate combat while possessing the corpse of a recently killed creature.

Bhut

Medium undead (shapechanger, spirit), neutral evil

Armor Class 10
Hit Points 38 (7d8 + 7)
Speed 30 ft.

Saving Throws Con +4, Wis +5
Damage Resistances acid, fire, lightning, thunder; bludgeoning, piercing, and slashing from nonmagical weapons
Damage Immunities cold, necrotic, poison
Condition Immunities charmed, exhaustion, frightened, grappled, paralyzed, petrified, poisoned, prone, restrained, unsettled
Senses darkvision 60 ft., passive Perception 12
Languages any languages it knew in life
Challenge 3 (700 XP)                              Proficiency Bonus +3

Foul Presence (psionic). Each creature that ends its turn within 5 feet of the bhut must succeed on a DC 12 Constitution saving throw or be poisoned for 1 minute and infected with rotting flesh. Rotting flesh is a disease that takes 1d12 + 12 hours to develop symptoms.
Symptoms include feeling chilled, a wheezing breath, and seeing hallucinations of the bhut. The infected creature gains one level of exhaustion that can’t be removed until the disease is cured.
After finishing a long rest, an infected creature must succeed on a DC 12 Constitution saving throw or its Constitution score is reduced to half until the disease is cured.
A creature that succeeds on its saving throw against being poisoned is immune to the bhut’s Foul Presence for 1 hour.

Incorporeal Movement. The bhut 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.

Shapechanger. The bhut can use its action to polymorph into any beast with a challenge rating no higher than 3, or back to its true form. It takes on the statistics of its new form, except it maintains its own Intelligence, Wisdom, and Charisma scores and has its Foul Presence trait. If its hit points are reduced to 0, it returns to its true form.

Spirit Boundary. The bhut can’t enter a room with burning incense.

Actions

Desiccated Touch. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 10 (2d6 + 3) necrotic damage plus 10 (3d6) poison damage. The target’s hit point maximum is reduced by an amount equal to the poison damage taken. The reduction lasts until the target finishes a long rest. The target dies if this effect reduces it hit point maximum to 0. A target slain in this manner can’t be raised until the bhut is destroyed.

Etherealness (psionic). The bhut 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.

Possess (psionic). The bhut’s possession save DC is 14 (Charisma based). It is a Controller that can possess a dead beast or humanoid within 5 feet of it. When the bhut possesses a target, its body assumes a spiritual form and is subsumed by its host.

The bhut takes on the statistics its host had in life, and its hit points are restored immediately after possession. It maintains its own Intelligence, Wisdom, and Charisma scores and can use its Foul Presence trait.