Marrow Shards

A point of damage to every attacker reads as nothing, which is exactly the trap. The spell lands during the declare-attackers step, all at once, precisely when a go-wide deck has committed bodies it cannot pull back: tokens, mana dorks, one-toughness threats, the whole swarm cleared in a single beat. What makes it a genuine ambush rather than a fair sweeper is the Phyrexian alternative cost. Two life pays the entire bill, so a deck with no white sources at all can hold it back, and a player tapped out on their own turn can still wipe an attacking board on the opponent's. An opponent who reads an empty mana pool as permission to swing wide is misreading the board: the answer costs nothing to deploy. The life payment is also the restriction that keeps the card from being free safety against the decks it punishes. Against a fast clock, two life is a real cost, and the spell only ever shaves one point off everything, so it answers the swarm while doing nothing to a single fat attacker. The lasting lesson is on the attacking player's read. A tapped-out opponent with a card in hand is not a defenseless one, because mana stopped being the gatekeeper the moment the cost moved to life.