Steer Clear

White's cheap combat tricks-as-removal usually cap around two damage for a single pip: enough to trade with the small creatures the color fights on the ground, rarely enough to swing a race outright. The conditional here rewrites that ceiling. Control a Mount and the same one-mana instant scales to four, clearing the mid-sized attackers white normally has to chump or double-block. It is a Mount-tribal payoff dressed as a spot-removal spell, and the gating is deliberate: the card checks for a Mount as you cast it, so the bonus is a deckbuilding commitment rather than a lucky draw. Restricting the target to attacking or blocking creatures is the other half of the price. This is combat-only removal, live only during a declared attack or block, useless against a creature idling with no combat assignment or a value engine that never enters the fray. That constraint keeps the four-damage mode honest by tying it to the phase where white already wants to be spending mana, on either side of the board: it snipes an attacker before damage, or it punches through a chump blocker to keep an offensive rolling. The reward structure points one direction, toward the aggressive Mount deck that stays on plan: keep swinging, keep a Mount in play, and a single pip answers most of what stands in the way.