Argentum Armor
Artifact — Equipment
Equipped creature gets +6/+6.
Whenever equipped creature attacks, destroy target permanent.
Equip
Mirrodin's creator still lives, still shapes metal, and still commands world-shaking power.
Matt Cavotta
Rulings
You may target any permanent with the triggered ability, not just one controlled by the defending player. If no other player controls a permanent, you must target one of your own.
(wotc • 2011-01-01)
The second ability triggers and resolves during the declare attackers step. The target permanent will be destroyed before blockers are declared.
(wotc • 2011-01-01)
Rulings
You may target any permanent with the triggered ability, not just one controlled by the defending player. If no other player controls a permanent, you must target one of your own.
(wotc • 2011-01-01)
The second ability triggers and resolves during the declare attackers step. The target permanent will be destroyed before blockers are declared.
(wotc • 2011-01-01)