Eevee

The habitat assigned to it by the Pokédex is urban. Not forest, not cave, not mountain: you find it near people, in vacant lots and streets on the outskirts, and that closeness to humans explains half the species. It measures 30 centimetres and weighs 6.5 kilograms, so it fits on a lap.

What is unusual about it is not the body but the code. The entries repeat the same idea from the beginning, using different words: “irregular genetic makeup”, “unstable genetic code”, a configuration capable of mutating and adapting immediately to any environment it lives in. No other species has an official Pokédex entry that insists so much on its own instability, and no other one admits that the reason is still unclear. One of the more recent descriptions takes the idea into uncomfortable territory: its genetics are so sensitive to its surroundings that its face can end up resembling its Trainer’s.

That is where the eight evolutions come from, more than any other Pokémon has. The official category, Evolution Pokémon, describes less an animal than an intermediate state: the trunk of a line that only ends somewhere else. Radiation from several Stones is, according to the Pokédex itself, one of the triggers.

Its 325 base points are distributed almost evenly and are below what you need for anything: 55 HP, 55 Attack, 50 Defense, 45 Sp. Atk, 65 Sp. Def and 55 Speed. The highest figure is defensive and the lowest is offensive, which points to a wall that cannot take hits either.

Adaptability is the Ability that gives it some purpose: it raises the same-type attack bonus from ×1.5 to ×2, so one of its Normal-type attacks hits as if it had 55 Attack and double power. The problem is that Normal-type moves are super effective against nothing, are resisted by Rock and Steel, and are ignored completely by Ghost types. Last Resort, at level 55, has 140 power and with Adaptability becomes the strongest hit in its repertoire, but it requires having used all the other moves on the team first. Double-Edge, at 50, hits for 120 and sends a third of the damage back to a body with 55 HP. Quick Attack, at 10, is the only thing that lets it move first.

Run Away is only useful for escaping from wild Pokémon, and Anticipation is limited to giving you a warning. Coverage exists but does not deliver: Bite at level 25, Shadow Ball and Alluring Voice by TM, all of them backed by 45 Sp. Atk.

Where it does work is at the start of a normal playthrough, until you evolve it, and in support teams built around Baton Pass (level 35), Helping Hand and the Wish it inherits from the Egg. Outside that, any of its eight evolutions does the job better.

It belongs to the Field Egg Group, the most populated in the game, so the list of possible partners is enormous. The complication is the sex ratio: only 12.5% of specimens are female, seven males for every one female, and without that female breeding starts with a Ditto.

The 35 Egg cycles work out at roughly 9180 steps, among the longest stretches there are for a basic, non-legendary species. It comes from the Egg with Wish and Yawn, the two that make the trip worthwhile, along with Detect, Curse, Double Kick, Tickle, Flail and Mud-Slap.

The evolution conditions leave no room for approximation. Water Stone for Vaporeon, Thunder Stone for Jolteon, Fire Stone for Flareon. Friendship of 160 or more and levelling up during the day for Espeon, and the same at night for Umbreon. Leafeon and Glaceon depend on the location—Eterna Forest and Sinnoh’s Route 217, among others—or, since they were introduced, on the Leaf Stone and Ice Stone. Sylveon needs to know a Fairy-type move and have Affection of 2 or Friendship of 160.

Its catch rate is 45, the figure of a Pokémon that is difficult to catch despite how common it seems, and its base Happiness of 70 shortens the road to the two Friendship-based evolutions. It grows on the Medium Fast experience curve, one million experience points by level 100, and gives 1 Sp. Def EV.