Lethal Sting

Unconditional creature destruction at three mana is a rate black has held for a long time, and the additional cost here is doing something cleverer than a downside. The -1/-1 counter must land on a creature you already control, which means the spell is never quite free even when the target is worth killing: you pay in your own board's durability. Point it at nothing but a fair kill spell and it is overcosted, a strict downgrade you accept only when the counter has somewhere useful to go. That is exactly the design logic, though: rather than tax the card with a flat drawback, the cost routes its value through a specific archetype, so the counter reads as friction in a vacuum and as fuel among cards that want it. A creature that already wants to shrink, a body feeding a sacrifice outlet, a token you can spare the toughness on: any of those turns the additional cost into a second event, and the removal shows up with a rider attached. The destroy clause itself is plain and total, no exile, no restriction on what it hits, which keeps it live against the resilient threats that walk through damage-based removal. What you are actually evaluating is whether your board can absorb a counter every time you want to point this at something, and how often that counter does work instead of just parking on a creature you would rather have left whole.