As Luigi exited the Secret Altar he got everybody he had seen into the Foyer. "Get out of here!" yelled Luigi. "You'll end up in the fifth dimension if you don't!"
Nobody else said anything, but did as Luigi said. The three princesses all got out, followed by Pikachu and the other Pokémon, and lastly came Luigi; and as soon as they exited, the whole mansion imploded and faded into a vast, empty space.
Back at the lab, Luigi went to the professors with his last ghosts. "Well, this'll mess with your head," Prof. Oak said, "but all your hard work lasted only a single night! Well done, Luigi!"
"Thanks a lot!" Luigi said.
"No, Luigi, thank you for helping us out," said Prof. E. Gadd. "The mansion those Boos built disappeared into the night, but that treasure seems to be real. I have no interest in such stuff, so go on and keep it all! Use it however you like!"
"So it was all just a phony," said Pikachu sadly, "but at least Luigi is rich."
"Say what?" Prof. Oak said. "Enough rattling on