This horned mask is fashioned into the fearsome likeness of a pale oni. The mask has 6 charges for the following properties. The mask regains 1d6 expended charges daily at dawn. Spells. While wearing the mask, you can use an action to expend 1 or more of its charges to cast one of the following spells (save DC 15): charm person (1 charge), invisibility (2 charges), or sleep (1 charge). Change Shape. You can expend 3 charges as an action to magically polymorph into a Small or Medium humanoid, into a Large giant, or back into your true form. Other than your size, your statistics are the same in each form. The only equipment that is transformed is your weapon, which enlarges or shrinks so that it can be wielded in any form. If you die, you revert to your true form, and your weapon reverts to its normal size.