Bolas's Citadel [War of the Spark Promos]

Set: War of the Spark Promos Type: Legendary Artifact Rarity: Rare Cost: {3}{B}{B}{B} You may look at the top card of your library any time. You may play the top card of your library. If you cast a spell this way, pay life equal to its converted mana cost rather than pay its mana cost. {T}, Sacrifice ten nonland permanents: Each opponent loses 10 life.