As an action you can consume a certain type of metal to gain temporary effects until the end of combat (effects may combine if metal is an alloy)
Gold - temporary +1 to AC
Silver - +20 ft of movement
copper - Heal's you by 1d6 (2d6 at level 3, 4d6 at level 8, and 6d6 at level 13)
Iron - Elemental Resistance (at Dm's decision) 
Steel - Immunity to petrification

you target one enemy within 30ft of you and force them to make a DC 10 Constitution saving throw, if failed, the enemy is deafened until their next turn.