Bramblesnap

The trick this card pulls is converting your board's width into a single creature's height, and then forcing it through. The cost is tapping an untapped creature, so every body you control that has not yet committed (tokens with nothing worth attacking into, summoning-sick stragglers, a freshly cast blocker) becomes a +1/+1 you can stack onto one attacker. Because the activation has no built-in cap, the only ceiling is how many untapped creatures you have to feed it, and the trample is the part that pays off: those pumps land as damage that punches past a chump blocker rather than overkilling it. The design tension is that the engine is fragile in exactly the way go-wide decks are. It wants a wide board, but it taps that board down to grow, so a sweeper or a single well-timed removal spell on the snap itself collapses the entire math you just built. It rewards creatures that have already earned their keep on defense or that were never going to attack profitably, since any of them can still pay into the pile. As a payoff it sits in a familiar lineage of one-creature-as-finisher engines that ask you to commit your whole board and swing for everything: the kind of card that turns a clogged stalemate into a lethal attack step in one activation chain, and leaves you with nothing if the attacker gets answered before damage.