Frost Giant’s Plate

With only a thought you can make this fist-sized ball of jagged ice expand to encase your body in a frigid suit of plate armor constructed out of solid black ice. As a bonus action, you can reduce the armor to a 5 pound ball of ice which never melts, or expand the ice back into the suit of armor. While wearing this plate armor you gain a +2 bonus to Armor Class, resistance to cold damage, and once per day you can double your size (as the _enlarge/reduce_ spell) for 10 minutes.