Tibalt's Trickery

Counter target spell. Choose 1, 2, or 3 at random.
It's controller mills that many cards, then exiles
cards from the top of their library until they exile a nonland card witha different name than that spell.
They may cast that card without paying it's mana
cost. Then they put the exiled cards on the bottom
of their library in a random order.

"Clever girl"
— Robert Muldoon