A glitch makes it possible to get Mew in Pokemon Red, Blue, and Yellow.
Base method Edit
To use the glitch, you have to "escape" from a Trainer. You have to find a Trainer whose line of sight is the same size of the screen. (This means that if you are standing in front of them, they are just off-screen, and you approach them from above or from the side, then they will see you. This trick does not work when approaching a Trainer from below.) Position yourself so that the moment they appear on-screen, they will see you. Walk toward them, and use TELEPORT or FLY right as they see you. If you time it properly, you will be able to escape them without battling them. At this point, the Start menu will stop working until you start a battle; it is important, however, that you do not start any battles unless instructed to do so.
After you have done this, you must battle a Trainer that possesses a specific Pokemon (or combination of Pokemon). The most commonly-used Trainer is the one on Route 25 that possesses a Slowpoke. (The Trainer, if they are on land, must walk to you; if you walk directly in front of them, the game will freeze.) Once the battle is successfully completed, you need to return to the area where you "escaped" from a Trainer. When you arrive there, the Start menu will open on its own. Close it, and a battle with Mew will begin.
Mew's level will vary, ranging from 0 to 14; it is usually Level 7. This depends on whether or not Attack-modifying moves, like Growl, have been used; a variable is used to keep track of a Pokemon's in-battle stat modifications, with 7 representing an unmodified value.
Cerulean City method Edit
This method requires that
- North of Cerulean City, a Trainer stands in some tall grass to the left of Nugget Bridge. (This is Route 24.) You cannot have defeated this Trainer.
- You cannot have defeated the first Trainer (the Swimmer) in the Cerulean City gym.
- By extension, you cannot have defeated Misty.
- You must have a Pokemon in your party that knows TELEPORT.
Enter Cerulean City's Pokemon Center. Exit, and travel to and past the bridge to the north. Go left; a patch of grass should lie to your south.
Go directly above the Trainer in the grass, such that he is exactly one tile below the bottom edge of the screen. Take a step down, and the moment the Trainer becomes visible, press Start. If you've timed it right, you will be within the Trainer's line of sight, but the Start menu will be open. At this point, use a Pokemon to TELEPORT to Cerulean City.
After you select the move to use, the trainer will notice you and stop you; you'll teleport away before the battle can begin, however. Go to Cerulean City's Gym and fight the first Trainer. Return to the Nugget Bridge, and the Start menu will appear automatically. When you close the menu, a battle with a wild Mew will begin.
Slowpoke method Edit
This method requires that
- You cannot have defeated the Trainer on Route 25 that has a Slowpoke.
- You must be able to reach the Slowpoke Trainer without getting into any other battles. This requires that you have already beaten most or all of the Trainers along the way.
- You must have a Pokemon in your party that knows TELEPORT or FLY.
Escape from a Trainer using the method described above; FLY or TELEPORT to Cerulean City. Find the Trainer on Route 25 (near Bill's house) that has a Slowpoke, and walk into his line of sight (but not directly in front of him; he must walk to you, or the game will freeze). Defeat him, return to the area you escaped from, wait for the Start menu to open, close it, and you'll get to battle Mew.