Catching Mew
Make sure you didn't beat the guy in cerulean on your way to Bill's w/ the lv 17 slowpoke he's facing upward. make sure you also have the hm fly and can use it. on your way to celadon city from lavender town[the underground path] save right before you enter the door, go down a step and press start really fast[ if the gambler sees you shut if off and start again] fly to cerulean city got up to the guy w/ the lv 17 slowpoke and fight him once you defeat him [don't save or it'll mess up yur game] fly to lavender town start walking back towards safron city and on the narrow path the start button will pop up press b and a mew between lv 5-7 will apear it'll know only pound. NOTE: it might mess up your game when you get into battles there's a 90% chance it won't mess up and a 10% it will mess up when you battle[nobody won't be around and everythings blank or that's what happened in my blue game my red game it didn't mess up]