Pataphysical Cleave

Choose an opponent. That player splits your library into two face-down stacks. Exile the entirety of one of these stacks.

For each card exiled this way, reveal it:
-If it is a land card, add it to your mana pool, untapped.
-If it is a creature card with a mana cost you can pay, cast it without paying its mana cost.
—Put all other revealed cards into your graveyard.

The blade of decision cuts deep—one edge bleeds opportunity, the other regret.