Luigi's Mansion: Secret of the Boo's Crystal is a cancelled game and would've been the ninth installment of the Luigi's Mansion series. It was playable on the Wii U, and was gonna come out October 21, 2013. The game was rated T, so EEA Inc. had to cancel it, similar to Luigi's Mansion: BeWere of Luigi.

At E3 2013, EEA Inc. stated that the story include Bloody ghosts attacking Luigi, and going to collect parts of the "Boo's Crystal".

Spaceworld 2014 revealed a tech demo, showing 3 modes: 1 Player mode, 2 Player mode, and horror mode. 1/2 Player mode was shown to go through a mansion known as the "Googlie Mansion". Horror mode was a scarier mode, with blood, strong language, and seizured citizens. Mini-games were include with one of them, titled "Ghost_Catcher.JPG" recycled from BeWere of Luigi.