Jolteon, the lightning Pokémon.
Jolteon is the electric-type evolution of Eevee. Eevee evolves into Jolteon when exposed to a thunderstone.
Ash's Pokédex - Jolteon, the Lightning Pokémon. When angered or frightened, the hairs on Jolteon's body become like needles that are fired at it's opponents. It absorbs charged atoms and can produce 10,000 volts of electricity.