CLOAK OF NIGHT
Wondrous item, very rare (requires attunement)
A creature that is good in alignment that dons this cloak takes 4d6 psychic damage. The creature takes the damage each time it ends its turn wearing this cloak. The cloak's properties detailed below function only for a creature non-good in alignment.
While wearing this cloak in an area of dim light or darkness or at night, you have advantage on Dexterity (Stealth) checks, and Wisdom (Perception) checks made to see you have disadvantage. You also gain darkvision to a range of 60 feet.
While wearing the cloak in an area of dim light or darkness or at night, you can use your action to cast polymorph on yourself, transforming into a bat, crow, owl, or stirge. While you are polymorphed, you retain your Intelligence, Wisdom, and Charisma scores. You can use an action to change shapes or revert back to your original form. You can remain polymorphed for up to 2 hours per day or until you change back to your original form. After that, the cloak can't be used this way until the next dawn.