To do this code, go to 2 player vs. and select Mystic Cave. Go and die on the spikes and a "Y" will appear next to your lives. Keep on hitting the spikes. There will be an -> next to your lives and you will have 9 lives. Now you can beat the other player because you can die and various signs appear! Note: This is a glitch that does not work on all games and this only works on Tails.