Izzet Affinity leans on a colorless-heavy manabase (Urza's Tower, Planar Nexus, Petrified Hamlet, Urza's lands) that is shut down by Magus of the Moon and Blood Moon, and while Kozilek's Command isn't an artifact, threats like Giant's Boulder are artifacts we can profitably attack with Fiery Confluence's destroy-artifact mode, just as we can burn them out or wipe small tokens with the 1-damage-to-each-creature mode. Pithing Needle is strong against Karn, the Great Creator—unaffected by Karn's static ability—and is great naming Karn or a problematic repeatable artifact like The One Ring. Sundering Eruption is weak since it only hits a single land in a deck that floods the board with colorless mana sources, so we cut it along with Lavaspur Boots, which does little against their targeted-removal (Ugin, Eye of the Storms) game plan. Chalice of the Void at 0 hits Lotus Petal-style fast mana, but does not counter Force of Will or Force of Negation, which have mana values of 5 and 3.