Unlock Terrifying Invasion
Finish E-Boss: Stop the Knightmare and capture all 14 Boos belonging to Treacherous Mansion. The bonus mission remains locked if even one mission’s Boo marker is missing. The ten Boos caught in Ambush Maneuver count individually toward Treacherous Mansion’s fourteen. Check the mission selector and replay the missing Boo mission before attempting the unlock.
Clear six rooms in the order shown on your map
E. Gadd sends Luigi to six haunted rooms. The room order and ghost groups are randomized every attempt; there is no fixed six-stop route to memorize. The possible locations include Dark Age, Ice Age, Jungle, Ancient, Space, Aviation, Nautical and Train Exhibits, together with the Kitchen, Restrooms, Archives, East Corridor and Study. Use the current map to choose the next marked room, then clear every ghost before moving on. Empty rooms do not count toward the six required encounters.
Charge a wide Strobulb flash when several unprotected ghosts approach together. Remove sunglasses with the vacuum and wait for armed Greenies to uncover their faces. Clear Hiders, Sneakers and projectile throwers before attempting a long pull on a Slammer or Gobber. Stay away from a doorway’s edge while reeling in a ghost so an attack does not interrupt the capture. After the sixth room is clear, E. Gadd ends the mission. Make a separate collectible run if you still need gems; lengthy detours work against the quick clear sought here.
Revisit the lower mansion
Unlike many later story visits, Terrifying Invasion lets you return to the Bottom of the Well and lower catacombs. The spring flower provides the return route. Use this for missed basement diamonds after the timed clear attempt, and check the individual gem instructions for mission restrictions: not every story-specific challenge is available during the bonus mission.