Deadly Riposte

The tapped-creature clause is the whole design: this is punishment for a creature that already committed to the attack, or a reward for the deck that taps things down before it swings. That restriction is what buys the aggressive package: three damage kills most early bodies outright, and the two life it returns turns a defensive removal spell into a genuine tempo swing against the beatdown decks white most wants to fight. The lineage runs through white's long history of conditional efficient removal, the cards that ask you to meet a condition (attacking, blocking, tapped) in exchange for a rate white does not normally get. Where Pacifism or Journey to Nowhere answer any creature at the same cost, this one is instant-speed but only reaches a creature that has already turned sideways or been tapped down. The instant timing matters more than the number: cast during combat, it removes an attacker after the opponent has committed to it, killing the creature before its damage lands in a way a sorcery-speed answer would arrive too late to stop. The lifegain is not incidental padding; against decks racing to close, gaining two while removing a body is the difference between stabilizing and dying, which is exactly the axis white removal at this cost is built to defend.