Bone Hag

Grave Walker. The bone hag can move through other creatures and objects as if they were difficult terrain. She takes 5 (1d10) force damage if she ends her turn inside an object.

Necrotic Aura. Any creature that starts its turn within 10 feet of the bone hag takes 5 (1d10) necrotic damage.

Innate Spellcasting. The bone hag’s innate spellcasting ability is Charisma (spell save DC 16, +8 to hit with spell attacks). She can innately cast the following spells, requiring no material components:

At will: chill touch, minor illusion
2/day each: animate dead, ray of enfeeblement, shield
1/day each: blight

Reaping Scythe. The bone hag carries a reaping scythe, a magical scythe that serves as a conduit between the worlds of the living and the dead. She can ride the scythe as if it were a broom of flying, although she cannot attack with it while doing so. Only a bone hag can use a reaping scythe. If the scythe is lost or destroyed, the hag must craft another, which takes a year and a day.

Multiattack. The bone hag makes two attacks with her reaping scythe. She can replace one attack to cast a spell or use her Curse of Fragility.

Reaping Scythe. Melee Weapon Attack: +7 to hit, reach 10 ft., one target. Hit: 13 (2d8 + 4) slashing damage plus 7 (2d6) necrotic damage.

Curse of Fragility (Recharge 5–6). The bone hag targets one creature she can see within 60 feet. The target must succeed on a DC 16 Constitution saving throw or be cursed for the next minute. While cursed in this way, the target creature is vulnerable to bludgeoning, piercing, and slashing damage. A cursed creature can repeat the saving throw at the end of each of its turns, ending the effect on a success.

Illusory Appearance. The hag covers herself and anything she is wearing or carrying with a magical illusion that makes her look like another creature of her general size and humanoid shape. The illusion ends if the hag takes a bonus action to end it or if she dies. 

The changes wrought by this effect fail to hold up to physical inspection. For example, the hag could appear to have smooth skin, but someone touching her would feel her rough flesh. Otherwise, a creature must take an action to visually inspect the illusion and succeed on a DC 20 Intelligence (Investigation) check to discern that the hag is disguised.