Rethink

Mana Leak punishes the early game; this scales the other way, taxing the spell by exactly its own mana value rather than a flat number. The design tension is built into that equation: against a one-drop the counter is nearly a freeroll, but the tax it demands is also trivial, so it lets cheap spells slip through while clamping down on the big plays an opponent actually wants to resolve. The window matters. Hold it up and you are forcing your opponent to overcommit mana before they cast the bomb, or risk the counter when they tap out for it. Where Force Spike taxes one and Mana Leak taxes three, this asks for the spell's full weight, which means a six-drop must find six extra mana to push through. The friction is that it does nothing to a board already on the table and grows weaker as the game opens up and your opponents float more mana. It is a soft counter tuned for the midgame inflection point: late enough that the targets are expensive, early enough that the opponent has not yet banked the mana to laugh it off. The whole card lives or dies on reading that window correctly, which is a more demanding ask than the flat-tax counters it sits beside.