Anyone know what's up with Luigi's final smash?

[Powerstars]

When I first got Super Smash Brothers Brawl, I was interested in finding out what all the final smashes were. Especially Luigi. When I unlocked that mofo, and finally got to play as him, I saw a smash ball. I got it, and was eager to try out his final smash. I half-thought that it would be a color swap of Mario's. When I tried it out, my eyes were met with this:

So, does anyone know why they chose this final smash for Luigi?

 

[Luigisama]

probably has to do with luigi's mansion.

 

[CowboyFromHell]

Oh, I actually know this one.
It's Luigi's shadow dance, and has to do with his frustrations of constantly living in his brother's shadow. Kind of a repressed emotion attack or something haha.

 

[BSP]

It has something to do with Weegee being in Mario's shadow all the time

Regardless of source, it's an amazing FS.

 

[TheWinrar]

It's called the Negative Zone. Along with the aforementioned shadow stuff, it may also be a reference to the Minus World.