Knowledge Pool [Mirrodin Besieged]

Set: Mirrodin Besieged Type: Artifact Rarity: Rare Cost: {6} Imprint — When Knowledge Pool enters the battlefield, each player exiles the top three cards of their library.Whenever a player casts a spell from their hand, that player exiles it. If the player does, they may cast a spell from among other cards exiled with Knowledge Pool without paying its mana cost.