She's a model swap. She looks like Peach, but has Jigglypuff's moves and voice. You get her from picking Jigglypuff. That's why it looks like a freak of nature.
I would try to use Homebrew and some hacks myself, but I don't really want to risk my family's Wii.
If it was my own Wii I would try without hesitation.
Sorry to take place of Baby Luigi, but we haven't attempted vertex hacking in a while. I hope that somebody can use Baby Peach's model from Mario Kart Wii and import it into the game, though.
Double post, but I changed the name of the topic so it includes screenshots from all games.
And I have some screenshots to show you what happens when you get electrocuted in Super Smash Bros. See whose skeleton you can identify (yeah, it's only four people).