Luigi's Mansion: Dark Moon brings local multiplayer to the ghost-busting series when it arrives on 3DS in March. The reveal comes via the game's description on Nintendo's website, which notes "a brand new local multiplayer mode," one which may well have been lurking in the shadows for some time.
Curiously, the summary on the same page details the 3DS game as "1 player." Then again, it also offers an outdated 'March 2013' release window, which has since been upgraded. The return of Luigi and his foreboding abode is now set in tombstone for March 24.