Invoke Terror

Choose target opponent. Choose a nonland card
name. That opponent reveals cards from the top
of their library until the named card is revealed.
Exile that card, then that player shuffles their
library. Your opponent repeats this process on
you. For as long as the cards remain exiled,
players may cast the card they exiled from their opponent's library, and spend mana as though it
were mana of any color to cast it.