Lvl 100 Mew after the first 2 gym leaders
First you must not have beat the person with the lvl 17 slowpoke after the nugget bridge or the person left of the nugget bridge in the tall grass. Also, you must have an abra and a Pokemon that knows growl. Now go to the top of the nugget bridge and position yourself on top of the trainer in the tall grass but you can't see him on the screen and SAVE. Now step once down and quickly press start before you battle the person in the tall grass. Choose abra and teleport back to cerulean. Go back up the nugget bridge and battle the person with the lvl 17 slowpoke. Use you're Pokemon that knows growl and use growl 6 times and then defeat the slowpoke. Now go back to the nugget bridge. On the way, the start menu should pop up. Press B and you will face against a lvl 1 MEW. Catch the Mew and then put it in the front of your party. Now go to the grass area is to the left of the nugget bridge. Once a wild Pokemon appears, switch it out with another Pokemon and defeat it. Now you're Mew should lvl up 99 times!!!
Added by: dairyman8889 Jul 7th 2007, ID#4673