Midnight Banshee

The upkeep trigger turns the whole board into a clock that ticks against everyone but you. Every turn, each nonblack creature accrues another point of permanent shrinkage: small bodies die outright, larger ones erode toward zero, and the only survivors are the black creatures the controller chose to play. That asymmetry is the entire point. Wither on the body reinforces the theme, letting combat damage persist as lasting reduction rather than wiping clean between turns, so blocking or being blocked compounds the upkeep grind. The cost is the discipline here: a triple-black price tag commits the deck to mono-black or close to it, which is exactly the deckbuilding tax that earns the immunity clause. Build wide with black creatures and the engine is one-sided; splash a green ramp creature or a white hatebear and you start poisoning your own board. The design reads less like a finisher and more like a slow-motion board wipe stapled to a 5/5: left unanswered for two or three upkeeps, it dismantles a creature-based opponent without ever attacking. That patience dates it to an era when black's answer to a developed battlefield was often a recurring tax rather than an instant sweep, and the card asks its pilot to win the long game by sheer accumulation of counters.