Piplup

Piplup bears semblance to a penguin chick. It has yellow feet and a light-blue body. There are two white spots on its chest that seem to resemble buttons on a suit. It also appears to have a blue cape. It has a circular, blue head with white circles around its eyes and a small, yellow beak. The light blue mark between its eyes above the beak resembles a small crown.

Piplup is the only Water-type starter Pokémon that cannot learn Water Gun.
It is, however, also the only Water-type starter Pokémon to learn BubbleBeam via leveling up.
Piplup is the most selected Sinnoh starter in the anime. It has been the starter of Dawn, Kenny, and Tyler.
Piplup and its evolution family are the only Pokémon that learn Drill Peck that are not part Flying-type.