Feedback Bolt

The damage output is a count of artifacts, which makes this a finisher with no fixed ceiling: in a board flooded with cheap servos, signets, or affinity bodies, the number on the stack scales straight off whatever you have already committed. That is the trade. Five mana is steep for an instant that asks you to have already built a board, and against any control deck the spell sits dead until you reach critical mass; this rewards a strategy deep in artifacts rather than lifting a thin one. What separates it from generic burn is the target restriction: it can point at a player or a planeswalker but never a creature, so it cannot trade for blockers or clear the way. It is purely a conversion spell, turning a stalled artifact army into a lethal bolt, an instant-speed reach button for a deck that already controls the board but lacks the swing to close. The design sits in a small family of payoff spells that read artifact count as damage, the kind of top-end that funnels a wide artifact deck's permanents into a single line to the dome. Its existence is a tax on the opponent's removal: clear the artifacts or eat the bolt.