in "black destroyer", a sentient creature that calls itself coeurl lives on an alien planet. when a human starship arrives, they find a coeurl but assume it is an unintelligent animal, and even allow it to come on board. the coeurl realizes it can feed on humans but plays along in order to learn more about them and their ship. eventually, however, it kills and feeds on one of the ship's crew. the crew suspects the coeurl did it and tries to prove it by feeding the creature organically bound phosphorus similar to that in the victim's bones, but the coeurl is smart enough to pass the test. it is later found out and tries to escape, but it is no match for the humans' technology, and in the end commits suicide.