The Mythical Pokémon Mew was inspired by an F4 Phantom Fighter Jet hidden in the arcade game Xevious. Similar to Galaga, Xevious is a 1982 arcade shooter originally intended to take place during the Vietnam War. Partway through development, the game was altered to feature a sci-fi aesthetic. However, a small fighter jet sprite was left behind in the game’s code, which would later inspire the creator of Pokémon.
After the sprite was discovered, rumors about how to make the jet appear in Xevious were spread across Japanese playgrounds and through gaming magazines. Pokémon creator Satoshi Tajiri was a fan of Xevious, and became intrigued by these rumors. When he eventually created Pokémon Red and Blue (originally Red and Green in Japan), he pitched the idea of a secret, unobtainable Pokémon to his fellow developers.
Dozens of designed Pokémon, including Tajiri’s secret Pokémon idea, were cut or altered from the beta of Pokémon Red and Blue due to the Gameboy’s limited cartridge space, according to an interview translated by DidYouKnowGaming on YouTube. Red and Blue were notoriously buggy and featured the most expensive debugging process in Nintendo history. After the debugging tools were removed, there was just barely enough space left to add a single Pokémon.
Mew’s Inclusion Helped Boost Pokémon Red & Blue Sales
Programmer Shigeki Morimoto was tasked with adding Mew to the game at the last minute. Because of the time crunch, he was also forced to create Mew’s design, sprite, Pokédex entry, and in-game stats. Mew’s design was later refined by Pokémon art director Ken Sugimori for the English translations of Red and Green, who toned down the fetus-like elements and created the modern Mew design. Ultimately, Mew was left unobtainable in game.
Despite the lengthy debugging process, numerous glitches, like Pokémon's famous MissingNo, remained in Red and Blue. A glitch involving using teleport or fly right as a battle begins allowed players to encounter it. Once Mew’s existence was confirmed, rumors of how to obtain it spread quickly across playgrounds. One popular rumor centered on the odd truck visible when surfing from the SS Anne. This is the only truck in the game and can only be reached through trading, but serves no purpose.
The rumors of Mew led to sales of Red and Blue skyrocketing, helping the Pokémon series become the media juggernaut it is today. Mew would eventually receive official releases via distribution events and a prominent role in the first Pokémon movie. Later Pokémon, like Celebi, Jirachi, and Victini continued the tradition of rare Mythical and Legendary Pokémon only being obtainable through events.
Source: DidYouKnowGaming/YouTube