Imagineer's Inkwell

{1}: Reveal the top card of your library. If it's a land card, put a charge counter on Imagineer's Inkwell. If it's a nonland card with a lower converted mana cost than the number of charge counters on Imagineer's Inkwell, you may cast it without paying its mana cost. Then, shuffle your library. At the beginning of the end step, remove all charge counters from Imagineer's Inkwell.