This staff appears to be a giants icicle, but it does not melt.
The staff has 5 charges and recharges 1d4-1 at the end of a long rest. If all charges are spent, roll a d20. On a 1 the staff melts and it destroyed.
As an action, you can make a 15ft cone of ice emit from Icicle. All creatures in the cone must succeed on a DC 14 Dexterity saving throw or take 3d6 cold damage, or half as much on a failure.
Proficiency with a Quarterstaff allows you to add your proficiency bonus to the attack roll for any attack you make with it.
This weapon has the following mastery property. To use this property, you must have a feature that lets you use it.
Topple. If you hit a creature with this weapon, you can force the creature to make a Constitution saving throw (DC 8 plus the ability modifier used to make the attack roll and your Proficiency Bonus). On a failed save, the creature has the Prone condition.
Notes: magic user, Versatile, Topple