Cut Down kills most of their key creatures — Gixian Infiltrator, Krark-Clan Shaman, and Refurbished Familiar (2/1) all fall to it — disrupting their sacrifice-and-recur engine. The extra Grim Bauble's -2/-2 also picks off Gixian Infiltrator or Krark-Clan Shaman cheaply while filtering draws with surveil later. This is a mirror-adjacent artifact grind, so Reckoner's Bargain is trimmed since both decks are already drawing extra cards and tempo/removal matters more than incremental life and card advantage. Keep your own Blood Fountain and Refurbished Familiar package intact to match their recursive value plan.