(Note: you have to catch Bulbasaur, Charmander, Squirtle, Pikachu, Omastar and Ninetales!) To get ChronoMew you have to pick Bulbasaur, Charmander, Squirtle, Pikachu, Omastar and Ninetales then at the battle screen press A, B, B, A, C-Left, C-Right then START. You should hear a mew's cry then gets lower then growls. It'll pause, press start to battle with your new ChronoMew. (WARNING!!! If you press any diffrent button to start the battle all data will be erased that is all.)