Spy Combo wants to cast Balustrade Spy and assemble mana dorks like Overgrown Battlement and Saruli Caretaker into a Lead the Stampede or Dread Return payoff. Cast into the Fire's one-damage mode can hit up to two targets at once, which picks off x/1 creatures like Elves of Deep Shadow or Quirion Ranger. It cannot kill Wall of Roots (0/5) or Tinder Wall (0/3), so don't count on it to clear those. Its exile-artifact mode answers a Lotus Petal if they haven't already tapped it, or a Food token from Generous Ent. Relic of Progenitus is excellent here: cracking it in response to Dread Return, or after a big Balustrade Spy mill, exiles every graveyard. That leaves Dread Return without a creature card to target, and a Dread Return already in the graveyard is exiled too, so its flashback (sacrifice three creatures) is gone. Since Spy Combo has almost no removal or interaction, this matchup is about going under their ramp before Troll of Khazad-dum or Lotleth Giant come online, so lean into the aggressive core plan. Trim Chain Lightning, Gingerbrute, and some redundant card-selection pieces for the proactive disruption.