this information comes from super smash bros brawl website
This character, the prince of the heavenly seas, appeared in the
Japan-only release "Densetsu no Stafy." He’s shaped like a star, but
maybe he’s really a starfish???
I’ll do it! I’m doing it!
...He never says anything like that.
His body shines bright.
He boldly does a spin attack!
But...he’s weak?
He’s rare for an Assist Trophy, as he can be attacked.
Sometimes you may wonder "Stafy, why did you even come here?!" But that’s part of his charm.
Owwwwwww!