Vaporeon underwent a spontaneous mutation and grew fins and gills that allow them to live underwater. They have the ability to freely control water.
Biology
Physiology
Vaporeon is a composite creature sharing physical traits of aquatic and land animals. It is a quadruped with three small toes on each foot and dark blue paw pads on the hind feet. Vaporeon's body is light blue with dark blue marking around its head and a ridge down its back. This Pokémon has a split tailfin that has been mistaken for a mermaid's in the past. It has a white ruff around its neck, and three fins around its head made of cream-colored webbing. It is said that rain will come within a few hours if Vaporeon's fins begin to vibrate.
Special abilities
It has evolved to become better suited to an aquatic lifestyle. In addition to developing gills, it has a cell composition similar to water molecules. This structure allows Vaporeon to melt into water at will and keeps it camouflaged as it swims.
Behavior and Habitat
Vaporeon is mostly found in urban settings and is rarely seen in the wild, but it can also be found near clean, fresh lakes.
According to Motofumi Fujiwara, a key person at Game Freak, Eevee was based on a vague childhood experience he had, He described seeing an "indefinable creature" and that Eevee was based on a drawing of all that he could remember of it.
Each one of Eevee's evolutions are based on the same design but are made to resemble their type.
Name origin
Vaporeon comes from vapor (the gaseous form of water) and eon (an immeasurably long period of time, presumably in reference to the concept of evolution). Eon is also a suffix shared by all Eeveelutions and was Eevee's prototype English name.