Viridian Scout

Built around a single answer it can give exactly once: pay three more mana, sacrifice the body, and shoot down something with flying. That narrowness is the point. Green has spent its entire history struggling against fliers, and the color's traditional fixes (reach, mass anti-flying enchantments, the occasional desperate fight spell) all keep the creature on the battlefield. This one trades itself away entirely, functioning as a spring-loaded removal spell that happens to block a ground attacker while it waits. The 1/2 body is there to survive a turn and represent the threat; the elf's real job is to die productively. Even the damage is rationed to two, enough to clear most early evasive aggressors but pointedly short of the larger flying threats green most wants gone, so the answer never feels like a clean trump. As color-pie engineering it is honest about green's relationship to the sky: the color gets to interact, but only at a steep rate, only at a heavy up-front mana cost, and only once per card. The result reads as a designer's note on how far green is allowed to reach upward, and the answer is: a little, slowly, and at the cost of its own life.