>>13980501>>13979940From Bulbapedia:
Prior to Generation IV, Piloswine can learn AncientPower by breeding or by evolution of a shadow Swinub caught in Pokémon XD. Despite this, it cannot evolve into Mamoswine in those generations because Mamoswine did not yet exist. This makes it and Lickitung the only Pokémon which could not evolve even if the criteria were met because their evolved forms were not yet created.
Face it, there's no reason to justify the bullshit GF is doing. Why can't it just be like this:
>Jolteon: Thunder Stone>Flareon: Fire Stone>Vaporeon: Water Stone>Espeon: Sun Stone>Umbreon: Moon Stone>Leafeon: Shiny Stone>Glaceon: Dawn Stone>Sylveon: Some new stoneIt would also make Eevee unique in the way that it could take just about any stone and use it to evolve.