Briber's Purse
Khans of Tarkir — uncommon
Artifact
Briber's Purse rulings:
2014-09-20: Activating the ability targeting a creature that’s already attacking or blocking won’t remove it from combat or affect that attack or block.
2014-09-20: If Briber’s Purse has no gem counters on it, it remains on the battlefield, although you can’t activate its last ability.