Contamination

A mana lock that bills you in bodies. The denial half is the brutal part: while it sits in play, every land that taps for mana produces black instead of whatever it would normally make, so an opponent off black who relies on lands finds any spell with a white, blue, red, or green pip simply uncastable, no funds to pay for it and no chance to put it on the stack. Generic costs still resolve (an artifact, the colorless portion of a spell), but a colored requirement the opponent cannot meet stops the spell before it ever launches. No attack required; the game just freezes. The catch lives in your upkeep, where each turn demands a sacrificed creature or the enchantment falls off, and that recurring tax is the entire design problem. The one clean answer is a stream of bodies that returns faster than the upkeep consumes them. Note the trap regeneration sets: it replaces destruction, not sacrifice, so a regenerator pitched to the upkeep cost is gone for good, shield or no shield. The archetype this anchored leaned on self-replicating tokens and creatures that came back to hand or battlefield on their own, turning the cost into a renewable resource while the opponent starved under hard color denial. Without that engine, the enchantment is a countdown that devours your own board; with it, the countdown never reaches zero. The whole prison hangs on one fragile prerequisite, and on a single question every upkeep: what is left to feed it.