Syncopate

Mana Leak taxes by a fixed three; Power Sink drains every land an opponent leaves untapped. This sits between them, with one defining property: the X you pour into casting it is exactly the X the opponent has to find to push the spell through. The counter is only as hard as the mana you sink behind it. That makes for an honest trade. Early, with little mana to spare, it is a soft tax that a flush opponent can pay around. A fixed-tax counter has the same weakness, and worse late, when opponents float more mana than three can ever demand. Syncopate's price instead climbs alongside your own resources, so in a long game with lands to burn it hardens into near-total denial. The cost is the inverse risk: it can sit useless in hand when you cannot back it with enough mana to bite. The exile clause is the wrinkle that earns its keep. Most counterspells are graveyard-neutral, but this one strips the answered spell out of the game entirely, which matters against escape, delve, reanimation, and anything that recasts from the bin. Counter a spell that itself carries flashback, cast from hand, and you remove it before its owner ever gets the second cast; counter a key reanimation target and it never returns to the yard to be looped. Where flexible, mana-hungry interaction is the goal and stripping a recursion piece is a bonus, the X is the feature, not the tax.