Grixis Affinity's entire plan revolves around cheap and free artifacts (Ichor Wellspring, the Bridge lands, Myr Enforcer, Refurbished Familiar), making Ancient Grudge a premium answer that can destroy an artifact creature like Refurbished Familiar or Utrom Monitor, or a non-Bridge artifact land like Seat of the Synod, Vault of Whispers or Great Furnace. It is best saved for real threats rather than Ichor Wellspring, which replaces itself when it is destroyed. Note that the Bridge artifact lands (Drossforge Bridge, Mistvault Bridge, Silverbluff Bridge) are indestructible and immune to it, and the flashback for {G} gives a second use. Electrickery's overload mode won't touch Myr Enforcer (4/4) or Utrom Monitor (3/3), but it cleans up their 1-toughness creatures like Krark-Clan Shaman and Refurbished Familiar, so it still has value against their cheap creature suite. We trim the slowest card-filtering pieces (Bitter Reunion, one Melded Moxite) for a faster, more disruptive game plan against their low curve.