Souldrinker

Black's life-as-currency theme is one of the game's oldest, and this is a fairly literal expression of it: an open-ended pump that converts life into permanent stats with no ceiling and no end-of-turn fade. The interesting tension isn't the rate, which is steep, but the resource it taxes. Most pump effects spend mana, something you regenerate every turn; this one spends only life, which only goes down. There is no mana gate on the ability at all, which makes the math purely a function of how much of your life total you are willing to mortgage. Each counter is a one-way transaction, more dangerous the longer a game runs, weighing survival against board presence with every activation. The 2/2 body is deliberately undersized for four mana, because the counters are the point: left alone with life to burn, it can become an arbitrarily large attacker in a single activation-spree, untethered to any mana count. That same open-endedness is the flaw. The ability does nothing to protect the creature, so every life point sunk into it is hostage to a single removal spell, and three life per counter is a brutal exchange rate when the payoff evaporates on contact. It's a clean, honest articulation of black's life-as-currency philosophy from an era when that theme was still being mapped out: more a statement of color identity than a card built to win.