Solo>Stadium>Fourth option
To unlock Boss Battle Mode which is located in Stadium in Solo Mode you have to beat the Subspace Emissary.
Tabuu.
Tabuu.
No, it does not count as a playthrough when unlocking a challenge from the vault.
As a playable character no.
No.You cannot.
If the bosses' health is low throw the trophy stand at 'em
No, he is only a boss.
meta ridley
No you can't. He is only a boss
Yes, he is the final boss in the SUper Smash Bros Brawl story mode, but he is not a playable character.
I am pretty sure you can only face him in boss battle mode. sorry.