Bolas's Citadel [War of the Spark]

Description

Set:	War of the Spark
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 lands and cast spells from the top 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.