Staff of Frost

While holding this staff you gain resistance to cold damage, and you can use an action to expend charges to cast one of the following spells, using your spell save DC: fog cloud (1 charge), ice storm (4 charges), wall of ice (4 charges), cone of cold (5 charges).

The staff has 10 charges and regains 1d6+4 expended charges each dawn. When the last charge is expended, roll a d20\. On a 1, the staff melts into water and is destroyed.