Cat Seal

You can acquire one by starting a new game and only taking blue bonus professions and traits. This specific starter Catseal will have the special trait Lucky, which gives you an extra choice in Essence Portals.

They also very rarely show up in wandering enemy groups spawned from walkable water tiles, and can be captured like any other creature. There is an event that can trigger while dating Lumira on the beach that shows more art for the Catseal.