Sneak and Show wants to resolve Show and Tell or Sneak Attack to cheat in Emrakul, the Aeons Torn or Atraxa, Grand Unifier, so Force of Negation is a critical free counter to stop these enchantments/sorceries on their turn. Consign to Memory's replicate mode can stop multiple Lotus Petal-fueled plays or colorless spells, and it's cheap enough to hold up mana for your own threats. Meltdown at X=0 cleans up their Lotus Petals before they can ritual into Sneak Attack. Into the Flood Maw and Spell Pierce are too weak against their big top-end payoffs and Force of Will backup, and the extra Unholy Heat/Preordain/Flow State are trimmed since this matchup is decided by countering their key enchantments, not incremental card selection.