Amulet Titan depends on bounce-lands and Urza's Saga alongside Amulet of Vigor to generate explosive mana, so Blood Moon shuts off their nonbasic lands (Simic Growth Chamber, Gruul Turf, Urza's Saga) and strands Amulet of Vigor with nothing to untap. Meltdown is a cheap sweeper for their Urza's Saga constructs and Amulet of Vigor itself. We cut slow, situational cards for this proactive disruption package aimed squarely at their nonbasic-land-dependent engine.