It is a small, blue-and-white Sea Otter Pokémon with a detachable scallop on its chest (called a "Scalchop") that is made of keratin (the same stuff that is found in hair and nails) and is used as a sword. Its name may be a combination of ocean, shell, water, and otter, as well a reference to the Canadian city of Oshawa.
It was the least popular of the Unova Starters when it was first revealed, well behind that of Snivy and Tepig, and it was initially seen as a bastard child of a Piplup and a Bidoof. It was also given the rather unimaginative fan nickname "Wotter" before it received its official International/English name. However, it gained better reception after its evolutions Dewott and Samurott were revealed and gained further popularity after Pokémon Black and White were released.