Kozilek, the Great Distortion

Of the three titan Eldrazi cast off this number, this is the one built around the resource the others never bothered with: the hand. The cast trigger refills you toward seven cards on the way down, which is not card advantage for its own sake but ammunition for the second ability, a counterspell that costs a card whose mana value exactly matches the spell you want to stop. That exactness is the whole design: it is not "discard to counter," it is "discard a 4 to stop a 4," which turns a bloated hand into a battery of pinpoint answers and rewards a deck that runs a spread of mana values rather than a glut at one number. The interaction with zero is the wrinkle players seize on, though it is narrower than it looks: mana value is fixed by the printed cost, so an alternative-cost spell like Force of Will still counts as its full value regardless of what was paid, and only genuine zero-cost cards fall in that band. Unlike the titans that arrive with protection built in, this one has only menace on a 12/12 to keep it on the board; its real safeguard is the discard ability itself, which can counter the very removal aimed at it, but only if the right mana value sits in hand. That conditional defense is the tension: a finisher that polices the stack after it resolves, but one whose own survival depends on holding the exact answer when it matters.