Tests show that its cells closely resemble water molecules, which perhaps explains its ability to conceal its form while submerged. I believe the origins of mermaid folklore lie with this Pokémon.
vaporeon
Flare Blitz
charizard
451
skorupi
Grass/Fighting
decidueye
Stories go that it grabs the hands of small children and drags them away to the afterlife. It dislikes heavy children.
drifloon
Thunder
Pikachu
302
sableye
Dragon ground
garchomp
It learns martial arts that use punches and kicks. Every several years, its old feathers burn off, and new, supple feathers grow back in their place.
Blaziken
Hyper beam
Gyrados
598
ferrothorn
dragon/fairy
altaria
To steal the life of its target, it slips into the prey’s shadow and silently waits for an opportunity.
Gengar
Transform
ditto
846
arrokuda
water/fairy
azuril
he tail’s tip shines brightly and can be seen from far away. It acts as a beacon for lost people.
Ampharos
future sight
mewtwo
726
torracat
rock/fire
coalossal