Eevee
From Multiversal Omnipedia
Genetically unstable Pokémon, #133. It resembles a small puppy. Eevees only evolve into greater forms when exposed to the radiations of three types of stone:
- A Fire Stone transforms one into a Flareon.
- A Water Stone transforms one into a Vaporeon.
- A Thunder Stone changes an eevee into a Jolteon.
An eevee that is raised well may also evolve into a Espeon (if it evolves during the day) or a Umbreon (if it evolves during the night).
Other evolutions may be possible using other stones such as the Moon Stone or Leaf Stone (or from combinations of stones), but none have been seen as yet.