Asphyxiate

The "untapped" clause is the whole negotiation. Black has always paid for its unconditional destruction in one currency or another: a life payment, a "nonblack" carve-out, an end-of-turn delay, a regeneration loophole. Here the price is a single battlefield state. The creature has to be standing up, which makes this fundamentally an offensive tool. Cast it in your main phase before combat and it strips a blocker out of the way; the path is clear, and then you swing. What it cannot do is answer the thing that just attacked you, because that creature is tapped on your turn, sitting there as a problem you have to wait out. This is the inverse of how players reflexively want black removal to work: it is at its best clearing untapped defenders, not punishing aggressors. As a destroy effect it ignores toughness entirely, so it handles the large bodies that walk through a -X/-X shrink like Disfigure simply by being too big to die to it. The cost is that you do not dictate the timing as freely. The opponent chooses when their creatures are tapped, and an attacking deck will often leave you a board full of tapped beaters you cannot touch, then untap and present them again on its own turn. Removal that wants the target relaxed and idle is removal that asks you to find the lull, not the crisis.