Cephalopod

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

Throughout the universe, various cephalopodic species exist. This is one of the many shapes that recur throughout the universe, including insectoid and humanoid.

In the 51st century, cephalopods (or at least cephalopod-humanoids) may interbreed with humans. Ianto Jones expressed of his very near-human boyfriend, Jack Harkness, fear of a boyfriend leaving him equally for "men, women, or cephalopods." (TWN: The House that Jack Built)