Cephalopod

Cephalopods were a type of animal which included octopi, squids, cuttlefish and the like. (TV: Spearhead from Space)

Throughout the universe, various cephalopod species existed. This was one of the many shapes that recurred throughout the universe, along with insectoid and humanoid. The Nestenes were a sentient, hive minded race who, in their natural form, were cephalopods. (TV: Spearhead from Space)

Ianto Jones told his boyfriend Jack Harkness that he had a fear of a lover leaving him equally for "men, women, or cephalopods." (PROSE: The House that Jack Built)