Izzet Affinity ramps into Urza's Tower lands to deploy Karn, the Great Creator and Ugin, Eye of the Storms; Karn in particular punishes our artifact-based plan with his static ability. Disruptor Flute naming Karn makes him cost {3} more to cast, buying time before he enters and locks down our artifact activations, while also preventing his loyalty abilities from being activated. Swords to Plowshares removes opposing creatures like Thundertrap Trainer or Tishana's Tidebinder, and Engineered Explosives can clear their small permanents. We cut Karakas, which has no legendary creature targets in this matchup, and a couple of artifact mana rocks that are more exposed to Karn's static ability and less needed once we're playing a longer, more controlling game.