Mine Spell Unlocked
Select Codes in Options and enter kaboom.

Tornado spell
Enter "BLOWHARD" as a code to unlock the tornado spell.

Control victory stance
At the victory or game ranking screen, press A, B, X, or Y if you are the winner of the round and leader of the match to control your victory stance/taunt.

Fireball spell
Enter "STRIKEAMATCH" as a code to unlock the fireball spell.

Homing head spell
Enter "DODGETHIS" as a code to unlock the homing head spell.

Lightning bolt spell
Enter "KILOWATTS" as a code to unlock the lightning bolt spell.

Lightning cloud spell
Enter "STORMYWEATHER" as a code to unlock the lightning cloud spell.