Instructions
Unlock Lucario using one of three different methods. Lucario is unlocked naturally by playing through the Subspace Emissary story mode. Lucario can also be unlocked by defeating him in combat in Brawl mode. Play 100 matches in Brawl or defeat all five levels of Target Smash with a single character to make Lucario fight you. Defeat him to unlock him as a playable character on the Character Select screen.
Face your opponent during a fight. Aura Sphere is a ranged attack so you do not need to stand close to your enemy.
Press the "B" button by itself to fire an uncharged Aura Sphere. The Aura Sphere will shoot in the direction you are facing, but will travel up and down in a wave motion as it goes across the screen, making its movements unpredictable.
Press the "B" button by itself and hold it down to charge the Aura Sphere. Release the "B" button when the Aura Sphere is fully charged to shoot it at your enemy. A fully charged Aura Sphere does more damage, moves faster and follows a straight line instead of moving up and down.