Run Afoul

A sideways answer to the one thing green often has to fight through rather than remove: the flier it cannot block. Green does destroy fliers, but usually on its own creature-heavy terms, with reach bodies, fight spells, and mass "destroy target creature with flying" effects that hit the whole sky at once. This does something narrower and cheaper by never touching the flier at all. The sacrifice clause is the whole trick. It slips past hexproof and shroud, ignores toughness, and shrugs off protection, because the opponent simply hands one over. That design also carries the tax that keeps a one-mana instant this clean: the opponent picks which flier to lose, so a board with any spare evasive body turns your removal into a trade for their worst creature. It does real work when the flier is the entire plan (a lone bomb, a single evasive threat carrying a race) and curdles into a dead card the second there is a second flying creature to feed it. That conditionality is the point rather than a flaw. It is a reactive, situational tool priced for the days when green's opponent has committed everything to one thing in the air, and honest enough about its own narrowness that it lives in a toolbox rather than a maindeck slot.