Puyo Puyo Sun 64

Random character selection:
Go to the character selection screen, then highlight Lulu
and hold Start.

Unlock all characters are elephants
Go to the character selection screen, then highlight the elephant
and hold Start.

Unlock Dark Arle as playable character:
Select one player or two player mode. Hold R and press A
at the character selection screen.

Unlock Carbunkle as playable character:
Go to the character selection screen, then highlight Arle the
girl and keep held Start until Carbunkle appears.

Unlock Satan as playabler character:
Go to the character selection screen, then highlight Shin
and keep held Start until the Satan appears.