Oops! All Spells is a pure combo deck that aims to mill its entire library with Balustrade Spy or Undercity Informer, then win with Thassa's Oracle or Dread Return. Your primary interaction is speed — establishing a Dark Depths + Thespian's Stage or Urza's Saga lock before they can assemble their combo. Endurance is your most critical sideboard tool, as it shuffles their graveyard back into their library mid-combo, completely neutering Narcomoeba triggers and Dread Return reanimation. Surgical Extraction can exile a key combo piece like Thassa's Oracle or Balustrade Spy after disruption, stranding the rest of their graveyard engine. After sideboard they can bring in Lion's Eye Diamond and Beseech the Mirror for redundancy, so prioritize racing and apply pressure with your 20/20 threat as quickly as possible.