Slash of Talons

The restriction is the whole transaction: this can only fire once a creature has committed to combat, so it does nothing against a creature sitting back on defense and cannot preempt a threat before it moves. That clause is what buys two damage for a single white mana, a rate white removal rarely reaches without a hoop to jump through. White has always paid for cheap removal with timing or conditions (Condemn needs an attacker, Path to Exile gives up a land, Swords to Plowshares grants life), and this occupies the cheapest, narrowest corner of that tradition: a combat-only burn pulse whose entire usefulness depends on the opponent having already declared an attack or a block. Instant speed is the sole thing keeping it live, since it lets the spell resolve during the declare blockers step, after blocks are set but before combat damage, so a defender can tip a trade in their favor or pick off an attacker that overextended. Any other point in the turn and the card is dead in hand, which is the deliberate cost of the price tag. It is built to reward the player holding up mana behind a defensive board, not the one who wants to clear a path on their own turn.