Arcbound Javelineer

Modular usually functions as a growth mechanic: a creature enters with a counter, and when it dies it passes that counter on to keep an artifact board accumulating stats. This one bends the same counter into ammunition. Its tap ability spends counters as fuel for damage aimed only at attacking or blocking creatures, turning each stored +1/+1 into a one-time removal charge that fires precisely when a combat trade is on the line. That reframes what the counters are worth: a modular creature normally wants to hoard its counters until it dies and then donate them, but here they are a resource you can cash in early, at instant speed, to shoot down an attacker or blocker before combat resolves. Every shot subtracts from the pile you would otherwise be growing or handing off, so the card forces you to price a single defensive answer against the long-term arithmetic of a counters-matter board. The body itself is negligible; the value is the flexibility to hold a combat threat in check and still contribute its remaining counters elsewhere later. The pinpoint restriction (only creatures already committed to combat) is what keeps the ability from being general-purpose removal, and it rewards a deck built to keep replenishing the pile faster than the javelineer drains it.