Obsidian Charmaw blows up Eldrazi Temple, Ugin's Labyrinth, or Urza's Saga, costs less for each of their lands that could produce {C}, and leaves a 4/4 flier behind. Stubborn Denial is weak here since it only counters noncreature spells, and their key cards are creatures. Consign to Memory stays in: it counters colorless spells and triggered abilities, which covers Emrakul, the Promised End, Devourer of Destiny, and their cast triggers. Containment Priest and Vexing Bauble stay on the bench. Containment Priest only exiles nontoken creatures that enter without being cast, and all of their creatures are cast (Eldrazi Spawn are tokens), so it does nothing relevant. Their deck also has no free spells for Vexing Bauble to counter.

Containment Priest stays in the sideboard for this matchup. Their creatures are all cast, including Nethergoyf's escape and Detective's Phoenix's bestow from the graveyard, so the Priest's replacement effect does not stop them. It would also exile our own creatures returned by Phelia. Obsidian Charmaw comes in as a 4/4 flying threat that also destroys a nonbasic land, such as Blood Crypt or Raucous Theater. Their lands produce only colored mana, so expect to pay its full cost. Lightning Bolt is too small to matter against Nethergoyf and Moonshadow once they grow, so it comes out. Consign to Memory stays in because it has real targets: Mishra's Bauble and Nihil Spellbomb are colorless spells, and Orcish Bowmasters, Stitcher's Supplier and Fear of Missing Out all have triggered abilities it can counter. Keep the Fatal Pushes and Stubborn Denials in as they still answer their early creatures and protect your own threats.

Mystical Dispute is excellent here, countering their heavily blue spell suite (Teferi, Narset, Jace, counterspells) for as little as {U}. It can also answer Wrath of the Skies at full cost, since that spell is only white. It can't help against Supreme Verdict, which can't be countered. Consign to Memory handles Solitude's enter-the-battlefield trigger as well as colorless spells like Isochron Scepter. Lightning Bolt does kill Solitude, but only after its trigger has already exiled something, and Solitude is nearly their only creature, so Bolt has few targets to burn. Stubborn Denial is risky against Orim's Chant and Silence, which can stop us from casting it at all. Keep Leyline Binding to answer their planeswalkers and Solitude. Fatal Push only destroys creatures with mana value 2 or less (4 or less with revolt), so it can't answer planeswalkers or the mana value 5 Solitude and is low-impact in this matchup.