Cloak of the Bat

While wearing this cloak, you have advantage on
Stealth checks. In dim light or darkness, you can
use it to fly at a speed of 40 feet. If you are no
longer in dim light or darkness, you lose this
flying speed.
While wearing the cloak in dim light or darkness,
you can use your action to cast polymorph on
yourself, transforming into a bat. While you are
in the form of the bat, you retain Intelligence,
Wisdom, and Charisma scores. The cloak can't be
used this way again until the next dawn