I assume you mean a "final smash." This can only be obtained in 2 ways. The first is to break a Smash Ball by attacking it and then using ones standard special attack ("B" on a Gamecube controller). The other is to be losing by a significant number of lives in a battle, in which case you may spawn with a Smash Ball already in your possession (though this will not happen every life).
Hope this helps!
You can only install Super Smash Bros. Brawl on your Wii with a Super Smash Bros. Brawl disc.
No, Megaman will not be in and is not in Super Smash Brothers Brawl.
There is no Super Smash Bros Brawl 2.
You can not get Blaze in Super Smash Bros. Brawl.
Super Smash Bros. Brawl happened in 2008.
No, in fact Shadow isn't even in Super Smash Bros. Brawl. He is from the Sonic games. Sonic however, isn't from Super Smash Bros. Brawl but Sonic is in Super Smash Bros. Brawl.
Dark Samus will not be in super smash brawl.
No, Pichu is not a playable character in Super Smash Bros Brawl
Sadly, you can not be Rosilina in super smash bros brawl
Sorry but no, Birdo is not in Super Smash Bros. Brawl.
No, there is no Super Smash Bros. Brawl DS.
Super Smash Bros. Brawl happened in 2008.