Cephalopod

Cephalopods were a type of animal which included octopi, squid, and other related creatures.

Throughout the universe, various cephalopod species existed. This is one of the many shapes that recurred throughout the universe, including insectoid and humanoid.

Ianto Jones expressed of his very near-human boyfriend, Jack Harkness, a fear of a boyfriend leaving him equally for "men, women, or cephalopods." (TWN: The House that Jack Built)