I know there's a GameShark code that you can encounter wild level 255 Pokémon, is there a glitch to get level 255 Pokémon without cheats?
Actually, there is a glitch to get level 255 Pokémon. However, it does require having a pokémon above level 100 which I believe can't be obtained without cheats. What the glitch entails though is that you can feed the Pokémon above level 100 Rare Candies until it gets to level 255. Also, if you feed it another Rare Candy when it is level 255, it will oddly go back to level 0. As for encountering level 255 pokémon, there is currently no known glitch that makes that happen.