Amulet Titan relies heavily on searching: Scapeshift, Green Sun's Zenith, Summoner's Pact, and Malevolent Rumble all dig for lands or Primeval Titan. Shadow of Doubt shuts off a full turn of that searching (denying Scapeshift's fetch-up or a Summoner's Pact activation) while replacing itself, and Vexing Bauble is a cheap proactive threat that also stops the zero-cost Summoner's Pact-style free spells if they ever appear. We hold priority to counter Scapeshift and Primeval Titan with our full suite; cut Field of Ruin, since most of their key lands (Urza's Saga, Simic Growth Chamber) aren't worth using our own land drop to answer, and trim Tune the Narrative for more disruption.