Swallowed by Leviathan

The tax scales with your graveyard, which turns this into a soft counter that gets harder to buy out the longer the game runs. Set against the fixed-number taxing counters it descends from (Mana Leak, Daze, Miscalculation), the difference is that you set the number yourself, in the same instant, before the tax resolves. The surveil 2 is the mechanism: it fires before the counter, so even cast into an empty graveyard you can bin both looked-at cards and demand a payment of two, filtering toward the answers you want while raising the price at once. That sequencing is the whole engine. The fuel you commit and the counter you cast are one decision, not a turn's setup followed by a payoff, which is why the card ties two things that usually live apart (graveyard growth and permission) into a single stack object. Cast it with six or seven cards already binned and it approaches a hard counter nobody pays through; even at its floor, the surveil guarantees a minimum bite rather than a whiff. The cost is the same one every conditional counter carries: against an opponent flush with mana, the tax you can muster may simply get paid, and the surveil, useful as it is, does not stop them. Every card already in your yard is another rung the opponent must climb to resolve their spell, so the counter is at its most punishing in the shells that keep filling that yard for other reasons.