Izzet Prowess is a mirror-ish matchup where both decks race with cheap spells and small creatures, so efficient interaction against their key one-toughness threats matters. Stern Scolding counters creature spells with power or toughness 2 or less for a single blue mana, hitting Dragon's Rage Channeler, Monastery Swiftspear, and Slickshot Show-Off for free value on the stack. Blood Moon can be devastating since they run several nonbasic lands (Arid Mesa, Scalding Tarn, Wooded Foothills, Steam Vents, Fiery Islet, Thundering Falls) that become Mountains, crippling their blue mana for Cori-Steel Cutter triggers and Preordain/Expressive Iteration. Force of Negation loses some value since we're often the ones racing rather than protecting a long game, and Spell Pierce is a marginal cut to make room.