Zoyowa's Justice (173) (The Lost Caverns of Ixalan)

The owner of target artifact or creature with mana value 1 or greater shuffles it into their library. Then that player discovers X, where X is its mana value. (Exile cards from the top of your library until you exile a nonland card with mana value X or less. Cast it without paying its mana cost or put it into your hand. Put the rest on the bottom in a random order.)