Mew (ミュウ, Myuu) is a fictional character from the Pokémon franchise. In the Pokémon video games, it is a Psychic-type secret Pokémon that was discovered in the first group of Pokémon games: Pokémon Red and Blue, Green, and Yellow. Mew is the Red/Blue/Green/Yellow counterpart to the Gold/Silver/Crystal Celebi and the Ruby/Sapphire/Emerald Jirachi.
The name "Mew" refers to the sound made by a cat. Mew was secretly put in the game by one of the lead programmers, Shigeki Morimoto. When the Game Freak president, Satoshi Tajiri, found out about it, he told about it being in the game.
Mew is #151 in the Pokédex and could only be obtained through special events or by using a cheating device like Gameshark, or a game-enhancing device. Mew can also be obtained in the original issues of the Pokémon yellow and blue (US) by “cheat”. If you get a Pokémon early on (before going to Misty’s gym or defeating man to the left of the nugget bridge) that has growl (charmander has it from the start) and an Abra or a Pokémon that can fly but you can’t fly this early in game (you can get an abra in the grass next to the nugget bridge but be careful not to battle the man standing above that grass he’s needed later. After this go to the health center and heal, then go to the top of the nugget bridge and save. Head down to Misty’s gym, go straight and take a right and challenge hit the guy trainer in a pool to the right use growl 6 times on his shelder then defeat him. Go back to the fight a Pokémon that’s low enough in level not to level your Mew up to level 2, it will automatically level up to 100.