Concussive Bolt

Four damage to a face for this much mana is a poor rate on its own, which tells you the spell was never priced on its first line. The metalcraft clause carries the card: with three artifacts in play, every blocker your opponent controls sits out the turn, opening a clear lane through a board that was otherwise stalled or trading evenly. That makes it a finisher for an aggressive artifact deck that has already committed bodies and now needs to shove the last chunk of damage past a wall of defenders. The design tension is the one every metalcraft card runs on: the artifact count that switches the spell on is the same investment that builds the board you need for unblockable damage to actually matter, so it pays off a deck already flooding the battlefield and does nothing for one that leans on it as raw reach. Read the target line carefully: it hits a player or planeswalker, never a creature, so it cannot trade for a blocker the way a conventional burn spell can. It knows only how to attack life totals and loyalty, then clear the path so everything else you have can do the same.