This is the exact mirror match against another UR Spellementals deck, where the player who develops a resilient threat and chains spells more efficiently wins the race. Colorstorm Stallion's ward and growing Opus ability make it a strong proactive clock that's hard for them to remove with Burst Lightning or Prismari Charm's 1-damage mode. Impractical Joke's 3 damage can't profitably kill their Eddymurk Crab or Hearth Elemental once discounted onto the battlefield, so it is weak here; Secret Identity is also cut since both decks are racing rather than looking to protect blockers. Ghost Vacuum isn't actually in our sideboard, so we correct course here: only Colorstorm Stallion comes in for Impractical Joke, with Secret Identity staying in as a useful combat trick alongside the rest of the core plan.