Restless Reef [The Lost Caverns of Ixalan]

Set: The Lost Caverns of Ixalan Type: Land Rarity: Rare Restless Reef enters the battlefield tapped.{T}: Add {U} or {B}.{2}{U}{B}: Until end of turn, Restless Reef becomes a 4/4 blue and black Shark creature with deathtouch. It's still a land.Whenever Restless Reef attacks, target player mills four cards.