Mystic Forge Combo is built almost entirely from colorless artifacts and spells, which makes Consign to Memory a cheap, flexible answer. It counters colorless spells such as Kozilek's Command, Karn, the Great Creator, The One Ring, Mystic Forge and Grim Monolith, and it also counters triggered abilities such as Tezzeret's artifact-enters trigger or Urza's Saga chapter abilities. It does not stop activated abilities, so Giant's Boulder's mana and sacrifice abilities are safe from it; only the spell itself (or its enters scry trigger) can be hit. Pithing Needle can't shut off Karn's static ability, but it can name Karn to stop its loyalty abilities, or name Mystic Forge or Grim Monolith to stop the Forge's exile ability or the Monolith's untap ability and slow their mana explosion. Shuko and Cabal Therapy aren't useful since this matchup is a race to resolve our combo before they assemble theirs, not a creature fight. Keep Force of Will at full count to protect our combo from being out-raced.