Sneak and Show wants to resolve Show and Tell or Sneak Attack into Emrakul, the Aeons Torn, Griselbrand, or Atraxa, Grand Unifier. Magus of the Moon turns their nonbasic lands (Scalding Tarn, Volcanic Island, City of Traitors, Ancient Tomb) into Mountains, which can slow their mana development and stop their fetch lands from working. It does nothing once they've already assembled mana, and it also turns our own nonbasic lands into Mountains, so it needs careful timing. Surgical Extraction needs a target card in a graveyard, so it is best once a copy of Show and Tell or Sneak Attack has been cast or discarded (for example to our Thoughtseize). It then exiles the remaining copies from their hand and library. The mainboard Koma, World-Eater can't be countered, but it costs 7 mana and is too slow and clunky in a matchup that is a pure race, so it's the easiest cut. Our own Thoughtseize and Cabal Therapy remain the core proactive disruption to strip their key cards, such as Sneak Attack, from their hand.