Mew in depth
Two weeks before sending the game to the factory
It wasn’t planned. Shigeki Morimoto, a Game Freak programmer, added it during the final stretch of Red and Green, taking up the space that had previously been reserved for debugging tools, and without telling almost anyone on the team. The basic idea came from Satoshi Tajiri, who wanted a creature that existed inside the game but never appeared. Ken Sugimori, who supervised the design of the rest of the list, did not supervise this one.
Its appearance also has an engineering explanation: it was drawn as a simplified version of Mewtwo to take up as little cartridge space as possible. The clone came before the original.
One move every ten levels
Its level-up learnset resembles no other. It rises at exact intervals: Amnesia at 10, Baton Pass at 20, Ancient Power at 30, Life Dew at 40, Nasty Plot at 50, Metronome at 60, Imprison at 70, Transform at 80, Aura Sphere at 90 and Psychic at 100. It’s a staircase, not a progression, and it is written to read like a joke about itself: the Pokémon supposedly holding the genetic material of all the others learns Metronome, which randomly executes any existing move, and Transform, the speciality of Ditto.
The price of the joke is that the best move of its own type among those it learns by level appears at 100, when there is no battle left ahead. At level 1 it only comes with Pound, 40 power, and Reflect Type, which copies the opponent’s types. Any plan that doesn’t go through TMs from the first minute is a bad plan.
One hundred in everything
The spread of six identical figures was not an isolated idea. It was repeated later in Mythical Pokémon such as Celebi and Jirachi, until it became a signature of the category. The advantage is not obvious: a Pokémon with no statistical weak point can take any Nature, any item and any Effort Value spread without any choice looking wasted. In practice, that means you have to decide everything, and two Mew belonging to two different trainers may have nothing in common.
Its growth rate is Medium Slow and its base experience yield, 270, is among the highest in the game. Defeating it gives 3 HP Effort Points, a detail almost no trainer ever gets to check for obvious reasons.
Outside trainer battles, it had a second life that is remembered less often: in Pokémon Stadium it appears as a rental Pokémon once the first round of the Prime Cup has been cleared. Anyone who never made it to an event could at least play with one on loan, equipped with whatever the machine gave it, without getting to keep it.