Riverchurn Monument [Aetherdrift Prerelease Promos]

Set: Aetherdrift Prerelease Promos Type: Artifact Rarity: Rare Cost: {1}{U} 1, T: Any number of target players each mill two cards. (Each of them puts the top two cards of their library into their graveyard.)Exhaust — 2UU, T: Any number of target players each mill cards equal to the number of cards in their graveyard. (Activate each exhaust ability only once.)