Wondrous Item, very rare
This amulet crackles with dark energy, protecting the wearer’s mind and unleashing devastating cold magic in a time of need.
Notes: Value: 12,000 gp While wearing this amulet, the bearer has advantage on saving throws against spells and magical effects. In addition, once per long rest as an action, the wearer can cast cone of cold (as a 5th-level spell, save DC 18) without expending a spell slot.