Zeliophax, the Scourge

Ward-Sacrifice a nontoken permanent
{t}: Chose an instant or sorcery spell in your
graveyard whose mana value contains {x}, then roll
a d12. You may cast that spell without playing its
mana cost, and the value of {x} for that spell equals
the number you have rolled on a die this turn. If
you do, exile that spell. Activate only as a sorcery.