EEVEE has an unstable genetic makeup that suddenly mutates due to the environment in which it lives. Radiation from various STONES causes this POKéMON to evolve.

Pokemon Wiki for Eevee, this includes an analysis of its strengths, weaknesses, and the diverse array of moves it can potentially learn and utilize in battles

eevee
pokémon number 133
pokemon info eevee
eevee strengths
eevee weaknesses
eevee pokédex information
pokémon wiki
pokémon battle