Sinking Feeling

An Aura that locks a creature down, then sells the prisoner's controller a key they can never afford. The first half is plain soft removal: once tapped, the enchanted creature won't untap on its own, contributing to neither attack nor block. The second half turns a permanent answer into a wasting clock. The opponent can pay to free their creature, but every untap costs a mana and shaves a point off both its stats, so escape comes at the price of slowly erasing the thing being freed. A bigger body walks free a few times before the accumulated reductions finish it; a one-toughness creature kills itself the first time it tries to move. This trades on the design tension that the -1/-1 counter and wither era was built to mine: the counters the Aura hands out aren't incidental, they're live ammunition for everything else on the board that punishes a shrinking creature. Left alone, the lock holds and costs its controller nothing, keeping a tapped creature on the sideline. Pressured, it becomes a self-inflicted curse. The whole personality lives in where the decision sits: you don't choose how the locked creature dies, the opponent does, and each choice they make leaves them smaller than the last.