Atomize

Unconditional destruction of any nonland permanent has long lived at four mana in these colors: the Golgari template is broad, clean, and unfussy about what it points at. What separates this one from the pile of "destroy target creature or planeswalker" instants is the proliferate rider stapled to the back end. That clause does nothing to the removal itself, and that is exactly the point: it turns a piece of interaction into a second trigger for whatever counter engine the deck is already running. Kill the threat, then advance your own planeswalker loyalty, your saga chapters, your +1/+1 counter creatures, your poison clocks, all in the same instant-speed window. The design is doing quiet double duty. It answers the board and it pushes your own plan forward on the same card, so the tempo cost of holding removal up is partly refunded whenever you fire it. Proliferate is a symmetrical-looking word that is almost never symmetric in practice, because you choose which permanents and players get the bump; the removal buys you the tempo to make that choice matter. It is a removal spell built for decks that already care about counters and would rather not spend a whole card doing nothing but killing something.