Arbalest Elite
Three damage to an attacker or blocker, gated behind two costs that work in tandem: the activation layered on top of the body you already paid for, and a tap that surrenders the next untap step entirely. That second clause is the real governor. A pinger that untapped freely could threaten to shoot every turn, dominating combat math indefinitely; this one fires, then sits dormant for a full rotation, so each activation is a deliberate commitment rather than a passive deterrent. The body is built to survive what it shoots at: a 2/3 trades up against the small attackers an archer is meant to pick off, and the three-damage ceiling reaches past most of the early creatures it would face. The lineage is the long line of white defensive pingers that punish aggression without enabling it: a deterrent that wants the opponent to swing into it, not a clock that closes games. The friction in the cost is what separates this from the unbounded pingers of older designs; it is removal you ration, not removal you spam. And the timing matters: the ability fires in response to an attack or a block, at instant speed, which is the whole reason to hold the activation open through the opponent's combat rather than spending it on your own turn.
