Scrapyard Salvo

A burn spell whose damage is paid for in advance, by everything you've already thrown away. The conversion rate here is the whole engineering problem: it deals nothing on an empty graveyard and lethal on a full one, which means the card is really a payoff stapled to a deckbuilding mandate. You have to spend the early turns filling the bin with artifacts (cracked Spellbombs, sacrificed equipment, fetched-and-discarded relics) before the three mana means anything. That makes it a finisher that reads as a sorcery but functions as a clock you set several turns prior, and the reward scales with how aggressively your other slots treat artifacts as expendable ammunition rather than as permanents worth keeping. Note the targeting: it hits players and planeswalkers, never creatures, so it is pointed exclusively at the win condition, not at clearing the way to one. That restriction keeps it honest as a closer rather than a removal spell that happens to scale. It sits among a thin line of red effects that read the graveyard as a stockpile of damage instead of a recursion zone, converting attrition into reach, and it asks you to count dead artifacts as buried lightning. Build the artifact mill, and the last card you draw is the one that turns the pile into a kill.