Wand of Polymorph

This wand has 7 charges. While holding it,
you can use an action to expend 1 of its charges
to cast the polymorph spell (save DC 15) from it.
The wand regains 1d6 + 1 expended charges daily
at dawn.If you expend the wand's last charge, roll
a d20. On a 1, the wand crumbles into ashes and
is destroyed.