Pokémon Maryll

Maryll has an oil-filled tail that acts much like a lifeline. If you only see a tail bobbing on the water surface - that's a sure sign that Pokémon has dived underwater to get fed up with aquatic plants.

When Maryll catches prey in a fast stream of water, he holds himself with his tail by some tree on the shore. Pokémon has a very flexible tail, which also stretches well.