You have resistance to cold damage while you hold this staff. The staff has 10 charges. While holding it, you can use an action to expend 1 or more of its charges to cast one of the following spells from it, using your spell save DC: _cone of cold_ (5 charges), _fog cloud_ (1 charge), _ice storm_ (4 charges), or _wall of ice_ (4 charges). The staff regains 1d6 + 4 expended charges daily at dawn. If you expend the last charge, roll a d20. On a 1, the staff turns to water and is destroyed.