Alternative King Boo (Luigi's Mansion AU)

(This is an AU where King Boo is not the villain, as he is in the games. Instead, he's the Mario Bros best friend.)

The Mario Bros and King Boo have known each other for many years and been best friends. They gone through many adventures together, along with saving Peach from Bowser, of course.

But during a battle on a Spring day, Luigi found himself having visions of him, King Boo, and Mario, but not the way they were now. (Basically the visions were the classic Luigi's Mansion games).

King Boo and Mario are concerned about Luigi and his visions, worrying about him. But that wasn't the only thing Luigi was going through...