SMASH: MOTHER BRAIN

Have you guys ever tried to draw a brain? It ain't easy!

MOTHER BRAIN
NEUTRAL -Rinka- Mother Brain shoots a small circular projectile which will bouce off surfaces.
SIDE -Venom Breath- I didn't want to use the word spit, or puke or Mommy gobs loads of dreck on you. For this move she emits a poisonous liquid from an artificial orifice which remains on the stage for a short amount of time to continue dealing damage.
UP -Eject Blast- Shooting an explosion out of her robotic base, Mother Brain gains a small vertical boost.
DOWN -Electric Field She generates an electrical field around her which does glancing damage to airborne units but will do knockback damage to units in the field that are touching the ground. Like Raikou's ability in Melee.
FINAL -HYPER BEAM- A large, wide, multicoloured beam projects from Mother Brain's eye doing cumulative damage and launches upon completion. Can be directed up and down.

Why MOTHER BRAIN?
Woah, woah, what is this nonsense? Well, if you're going to suggest a new Metroid character, who else can you choose? One of those "Hunters" nobody remembers? Somebody from Other M who witty remark? Ridley?
I've actually already done Ridley and we already know his story but if you said "Dark Samus," here's INCOMING CONTROVERSIAL OPINION:
I think the single most creatively bankrupt thing you can do is make a "Dark [Character]" character, and while I did entertain the notion of altering the character slightly and classifying it as "Metroid Prime" that would have been a bit too much of a liberty and doesn't really fix the issue.
So I chose Mother Brain! An important element of the series, I'm sure you'll agree, but get this: As a brain, so won't even be that big! Roughly the same size or perhaps slightly bigger than Bowser, considering how she scales with Samus in her own games. We've also seen her function outside of the jar with the help of some sort of body that is possibly biological or maybe organic, I'm not completely sure. So I simply outfitted her with some Metroid Prime inspired legs and away we go! Surely you can appreciate the fun potential of seeing a big lump of flesh leaping about the place? You can't deny she's unique, at least.

What are her chances?
I think the developers realise that there's not a huge wealth of suitable Metroid characters for Smash, because it kind of goes against the entire series; That Samus is a small human alone on planets full of giant monsters, and that's why Zero Suit Samus has become a de facto second character. We have at least seen Mother Brain on the battlefield now but her playable chances? Less than 20% I'd say.

VERDICT
Alright, DEFINITELY less than 30%