Antithetical

Counter target spell or activated ability.
Direness {4}{u} (Any time a spell would be played,
you may search your library for a card named Antithetical and play it without paying its mana cost.
You can activate this ability even if Antithectial is not
in your hand. If this is True, the mana must be paid
by the end of your next turn or you lose
half your life, rounded up.)
"The answer is often concealed ", Jace Beleren.