Mystic Forge Combo is a slower artifact-based combo deck trying to assemble Karn, the Great Creator with The One Ring or Mystic Forge engines, so Force of Negation lets us proactively counter their key artifact or planeswalker spells for free on their turn before they lock up the game. Portable Hole can exile an early Lotus Petal, Grim Monolith, or other cheap mana-accelerant to slow their combo assembly. Fatal Push has essentially no targets against an artifact-heavy deck with few creatures, and Street Wraith's cycling matters less than disruption against their slower clock. This matchup is generally a race where resolving Doomsday before their engine comes online is the priority.