Frostbitten Buckler

Armor (shield), uncommon (requires attunement)

This icy shield has 3 charges and regains all of them each day at dawn. When a creature you can see hits you with a melee attack, you can expend 1 of the shield’s charges as a reaction to deal 2d4 cold damage to the attacking creature. After the attack, you gain that same amount of cold damage as temporary hit points that last for up to 1 minute.