Think that I've done that way back when I was young. Now go and figure out how to make Mario shoot fireballs while he is little and grow when he is touched by an enemy -_^
Actually I know what causes the little fire Mario.You got one address that stores if Mario is big or if Mario is small. A second address stores Mario's power-up. When Mario hits the axe and the fake Browser(sorry for spelling) the game only changes the address with Mario's power state, and because of this Mario will be big but with the power state beening small Mario. When getting a mushroom which changes the address that stores Mario's height to small because its not program to check to see if Mario is big or not and makes Mario small. Once Mario gets his hands on a fire flower, which is program to change
only the address that stores Mario's power state. This can be undone by restarting the game(bad choice) or killing Mario, with the latter beening the best choice(as long you have 2 lives) because the game resets both addresses when Mario dies.