Look on your map and go to a place near the end of the map with areas you cannot reach or go any further. First, ride your bike through a Route and encounter some Pokemon. Defeat some, catch some, run away from some, or damage a Pokemon's health once and run away. As soon as you hit the water's edge or an area that cannot be walked on (for example, trees or a stone platform), save the game. When you return to your game, immediately press the direction facing the obstacle that could not be walked or ran through to start running through the objects. The top screen will indicate that you have reached a place called "Mystery Zone” and there will be faint music playing, like that of the area where the PalPark is located. You might may bump into something but keep holding the D-pad and you will eventually get through. You will soon reach the game's limits where there is only infinite black abyss. Note: This is very difficulty to do, will require multiple attempts, and is not guaranteed to work with every game.