Harbinger of the Seas turns their bounce-lands (Simic Growth Chamber, Gruul Turf) and Urza's Saga into Islands, disrupting the green mana Amulet Titan needs to chain Amulet of Vigor triggers and cast Scapeshift or Primeval Titan. Consign to Memory can counter Amulet of Vigor itself, a colorless artifact spell, denying the free-untap engine that powers their whole turn before it starts. Stubborn Denial is unreliable since we're rarely ahead on board with a 4-power creature against a deck that just assembles lands, and Street Wraith's swampwalk does nothing here. Keep Thoughtseize and Fatal Push to strip Primeval Titan or disrupt their Scapeshift/Urza's Saga plan before they go off.