Tears of Valakut

Five damage at instant speed for two mana is a rate that would bend the color pie badly out of shape, so the design pays for that reach by gating the spell behind a single keyword: only a creature with flying is a legal target, and against a board without one the card sits dead in hand. That is the trade the narrow anti-flier hosers have always made, the Plummet and Whirlwind tradition of "answers the skies and nothing else," but most of those are slower, smaller, or exposed to permission on the way down. The wrinkle here is that this one cannot be countered. The decks most likely to lean on evasive threats are also the decks most likely to hold up blue mana, and that overlap is exactly where an anti-flier spell wants to resolve; making it uncounterable means a wall of open Islands cannot simply strand it. Being uncounterable is not immunity to everything, of course: a fog effect or a damage-prevention shield can still blunt it, and if the target loses flying or leaves the battlefield in response, the spell fizzles for want of a legal target. What the design buys is not certainty but a clean line through the one interaction that would otherwise punish a reactive answer against a reactive deck. The lopsidedness is the whole bargain: a card this restricted earns its slot by being fast, oversized, and hard to counter at the exact thing it does.