Sizzling Barrage

Four damage for two mana is a rate no unconditional burn spell gets, and the price is stamped into the target line: the creature has to have blocked this turn. That clause is the entire trade. This is not a flexible answer that picks off a threat whenever you like; it is a punish card, cast to turn a block the opponent thought was profitable into a lopsided trade. You attack, they throw a creature in front, and you spend two mana to erase it. The timing window is wider than it looks, though: the requirement is only that the creature blocked this turn, not that combat is still happening. Fire it in the declare-blockers step to kill the blocker before damage and keep your attacker alive, or hold it until the second main phase to finish off a blocker that survived the exchange. Either way the attacker stays blocked (assigning removal after blockers are declared does not let it slip through to the defending player), so the spell rewards a board already applying pressure rather than sitting back. Against straightforward two-mana removal the discount for the restriction is steep, and four damage handles almost anything an aggressive deck runs into, but the leash keeps it well short of a universal answer: it cannot touch a creature holding back on defense, and it is a dead card the moment the opponent declines to block.