A Quakken is a type of water-capable feral Submarine unit that will occasionally be sighted at sea. They have the girth of a whale and are shaped vaguely like a yellow dwagon, but have no appendages. How they propel themselves through the water is unknown. Their great beaks are orange, and their eyes a brilliant sapphire blue, but the rest of their bodies are a uniform bright yellow.
One of their favored foods is bread. They are not known to be fully tameable, but it is possible to make them friendly to a specific non-seafarer unit by having that unit feed them. While they cannot be given orders, they can sense the intent of the captain of whatever ship the unit they are friendly to is on board and will fight to protect it, even against other feral quakkens. As Duke Forecastle discovers, this will even work if the unit the quakken is bound to becomes a prisoner of an enemy captain. If the quakken is not fed again by start of next turn, or the landlubber it has been bonded to is lost, it will once again become hostile until placated by more food.