The evolution of Pokémon naturally wasn't like it was in the games, where they fought monsters and gained experience until they reached a certain level and evolved automatically, or used items like evolution stones to trigger the change.
This evolution was actually a hidden feature Belcher had built into the Pokémon when he created them. Eevee's Bionic Skin was semi-living, and its mechanical skeleton could extend. It was usually folded up, making Eevee look very small.
Once this ability was activated, the Pokémon would emit a blinding light that made it impossible to look directly at them. In truth, this was to keep people from seeing the horrifying sight of the Bionic Skin being torn open and then repaired. It would give children nightmares.
After Eevee triggered the ability, its body grew larger, and its Bionic Skin changed to match the evolution form it had been designed to take, perfectly covering its entire body once more. Depending on the type of evolution, its Energy Matrix would also change, granting Eevee special abilities it hadn't possessed before.
Clearly, faced with the Frost Giant's attack, this Eevee had chosen to evolve along the path of fire, becoming a Flareon.
Flareon had just melted the ice covering its body in an instant with its intense heat, then breathed fire at the Frost Giant's icicle, saving Jessica's life once again.
The Frost Giant was still stunned. The newly evolved Flareon had already pounced on it. Its sharp claws raked bloody gashes across the Frost Giant's body, but the creature's icy-blue blood froze before it could even flow out, seemingly doing little damage.
As the human and beast grappled, Trish, standing atop a high-rise, shouted, "Jessica, run! Bubu can handle this!"
Jessica had just seen Eevee breathe fire and melt the Frost Giant's icicle with