Heartseeker

The destruction clause comes with a built-in tax that defines the equipment: pulling the trigger means stripping it off your creature, surrendering the +2/+1 and forcing you to re-pay the equip cost before it threatens anything again. That single-use-per-attachment rhythm is the design's whole point. Each kill costs you a tempo cycle, so the equipment punishes you for treating it as repeatable removal while still rewarding you for keeping a creature alive long enough to set the trap. The sorcery-speed restriction lives in the equip step only; the kill activation itself is an instant-speed ability, which means a creature already carrying it can hold up an ambush in combat or react once the buff has done its job. The high equip cost is the other half of the math: at five mana to suit up, this wants a board where a single creature is worth that much investment, then converts that investment into a one-shot kill that resets the meter. It is an artifact built around the moment of decision rather than the rate, a piece of removal you spend rather than cast. The standoff between holding the stat boost and cashing in the kill governs how every line with it plays out.