Regain a lost life: Immediately enter the inventory screen after losing a life. Press A & B at the same time. The phrase 'Start Again' will confirm correct code entry. Select your character and resume game play with no lives lost.
Walk like a Mummy/Zombie: Leave the screen holding a box and hold the D-pad. When you get to the next screen, your character will not be holding the box, but he will continue to walk with his hands in the air above his head.