Harkness Test
What Is the Harkness Test?
Whether a fictional creature is able to consent for a sexual/romantic relationship
Face Huggers from alien.
No. While sexually mature they have way to communicate, I'm not sure how smart they are.
martian from war of the worlds
No.Big Smart. Big Adult. No communicate.
A.M from I Have No Mouth And Must Scream
Yes.
The Thing From the 1982 Movie The Thing
Yes. It is fully mature, has an intelligence and is able to communicate.