Bhut

Rot Aura (Night Form Only). Any creature that comes within 10' of the bhut and has a sense of smell must make a DC 15 Constitution saving throw or take 19 (3d10+3) poison damage and be poisoned for 1 minute. If the target succeeds on the saving throw then it takes half as much damage, is not poisoned, and is immune to this bhut's aura for 1 hour.

Deceptive Form (Day Form Only). When detect evil and good or similar magic is used on the bhut, its alignment shows as chaotic good. Even truesight only shows its humanoid form but with yellowish eyes as if it might be sick of joundiced. 

Shapeshifter. During the day the bhut transforms into a normal humanoid of medium size. Its equipment and clothind does not transform with it. All of the bhut's abilities (except where noted) remain the same in both forms. 
During the night, after the last bit of sunlight has vanished, the bhut transforms back into its true form, that of a ematiated, green skinned monster with long fangs and clawed hands, baleful yellow eyes, and a skeletal look to its frame, its skin pulled tight over its bones. 

Spellcasting. The bhut is an innate spellcaster. Its innate spellcasting ability is Intelligence (spell save DC 15, +9 to hit with spell attacks). The bhut can cast the following spells without needing material components:
At Will: Cause Fear, Chill Touch, Frostbite, [Tooltip Not Found] 
3/Day (Each): Crown of Madness, Darkness, Disguise Self, Misty Step
1/Day (Each): Hypnotic Pattern, Ray of Enfeeblement, Blight

Multiple Attack. The bhut makes three attacks, two with its claws and one with its bite or it makes one foul spittle attack.

Claw. Melee Weapon Attack: +9 to hit, reach 5 ft., one target. Hit: 17 (3d8 + 4) [Tooltip Not Found] until the end of the bhut's next turn.

Bite. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 22 (4d8 + 4)  piercing damage. If the target has 1/2 of its maximum hit points or less then the attack does an additional 9 (2d8) necrotic damage and the bhut regains hit points equal to the extra damage. 

Foul Spittle. RangedWeapon Attack: +9 to hit, range 40/60 ft., one target. Hit: 17 (3d8 + 4) [poison] damage and the target must make a DC 15 Constitution saving throw or be poisoned for 1 minute. The target can repeat the saving throw at the end of each of its turns to end the poisoned effect.