Cove of the Unremembered

Dungeons cannot attack or block.
Dungeon (Whenever a creature deals damage to this card, it may put an artifact card from any graveyard into their hand. Any player's creatures may attack this permanent during their owner's attack step)
Whenether an opponent's creature dies, flip a coin 2 times. If you win both times, exile it until Cove of the Unremembered leaves the battlefield.