Impenetrable Arm Shield (5e Equipment)

Armor (shield), legendary (requires attunement)

A nigh-unbreakable prototype shield, crafted from black wyvern scales and steel, capable of forming an unbreakable defense. Once, as a reaction to taking damage from a creature, you gain immunity to all sources of damage from that creature for 1 minute. Once this property has been used, it can't be used again until the next dawn.