Sarevok's Tome (685) [Commander Legends: Battle for Baldur's Gate]

When this artifact enters, you take the initiative. {T}: Add {C}. If you have the initiative, add {C}{C} instead. {3}, {T}: Exile cards from the top of your library until you exile a nonland card. You may cast that card without paying its mana cost. Activate only if you've completed a dungeon.