Sickening Shoal
Free removal that needs no land untapped and no mana spent: exile a black card whose mana value matches X, and the spell asks nothing else of you. That is the lever this card pulls, and it belongs to a small family of "Shoal" instants built on the same trade, Disrupting Shoal among them, each weaponizing a card-for-effect exchange to break the usual rule that powerful effects demand mana. The catch is the two-for-one and the matching tax: you spend two cards to kill one creature, and the pitched card has to share its mana value with the kill size, so taking down a four-toughness blocker means burning a four-mana black card you might have wanted to cast for real. Instant speed is what makes the exchange worth it. You hold up a hard answer with no mana committed and represent it the way you would a counterspell, killing a creature mid-combat or in response to a trigger, exactly the protection a tempo or combo deck wants on a turn it cannot afford to tap out. It rewards a hand stocked with expensive black cards you would rather not hardcast and sits dead in a hand that has nothing to feed it. The free cost is generous and the deckbuilding demand is real; the card lives entirely in the gap between them.
