Oops, All Spells! is a zero-land combo deck that wins as early as turn 1 by casting Balustrade Spy or Undercity Informer to mill its entire library, leveraging Narcomoeba triggers and Dread Return to put Thassa's Oracle into play. Grafdigger's Cage is your best permanent answer — it stops Narcomoeba from entering the battlefield from the graveyard and prevents Dread Return from functioning entirely. Force of Will and Daze are your primary interaction; Daze is particularly strong here since the opponent often deploys their combo with exactly enough mana, leaving them unable to pay. Consign to Memory handles Pact of Negation when they try to force through the combo, and post-board Null Rod shuts down Goblin Charbelcher along with their artifact mana (Lotus Petal, Chrome Mox, Lion's Eye Diamond). Cut the mana-denial package and slow threats — Wasteland and Boomerang Basics are nearly blanks against a deck with zero fetchable basics, and Cori-Steel Cutter is far too slow when the opponent can win on turn 1.