Raticate

Raticate (ラッタ Ratta) is a type Pokémon and the evolved form of Rattata starting at level 20. Its teeth are so strong, that Raticate is able to eat through cinderblock walls.

Appearance
Compared to Rattata, Raticate is far more of a predator, and the majority of its features are adapted for this purpose. Its most notable feature are its large teeth; like most rodents, Raticate's teeth grow continuously throughout its life, and must be constantly worn down by gnawing. It is also known that Raticate's fangs are tough enough to break concrete. It has long whiskers and a long tail. Raticate looks like a rat, just like Rattata.

Special Abilities
Raticate's webbed feet allow it to swim well when it hunts its prey.

In Anime
Ash traded his Butterfree to a gentleman on the S.S. Anne for a Raticate. However, he changed his mind and traded back. This was in Battle Aboard the St. Anne. The Kas Gym's Raticate was seen in the Showdown at Dark City. Butchs Raticate was seen in The Ole' Berate and Switch. Cassidy's Raticate was seen in The Breeding Center Secret, The Fortune Hunters, and Training Daze! Ralph's Raticate and Emily's Raticate where seen in Wherefore Art Thou, Pokémon? Molly's Raticate was seen in What I did for Love. And there have been other wild and owned Raticate in other episodes.

Origins
It seems to be based off of the nutria, or coypu. Whilst Raticate's name comes from rat and eradicate.

Trivia

 * In the Yellow Pokédex, it mentions that Raticate swims for prey, however, it does not learn Surf.
 * There once was an overlook in the anime where Rattata was standing next to Raticate. Raticate was actually as small as Rattata, which shouldn't normally happen.