Forced Landing

Green is the color of anti-flying, and this is the color-pie principle written out at its most literal: an instant that answers a flyer and nothing else. Green's fliers-hate has usually taken the form of reach on ground creatures, fight spells that need a body of your own, or mass-bounce that clears the sky along with everything else. This one gives green a clean, targeted answer, but it fences the effect off to the single thing green is allowed to hit precisely and cheaply. Bottom-of-library is the sharper half of the trade: unlike a bounce to hand, the creature does not get recast next turn, and the owner has to draw all the way back through their deck to see it again. (A commander is the exception; its owner may send it to the command zone instead, so the tempo hit there is only the recast tax.) The keyword restriction is what keeps the spell honest as a design: it is dead against anything on the ground, so it never drifts into being general-purpose green removal, and it is only ever castable when a flyer is already on the board. That last point makes the instant speed carry more weight than the rate suggests. The spell rewards holding it, waiting for the attack step, and blowing out the swing green would otherwise have had to absorb.