Scorpion alien

alien with a poison filled scorpion stinger, also the creature from the 1979 film, Alien. Starting out by hatching in a man's body, and exploding from his stomach, it then grew up on a space-ship and took each of the members one by one, until the woman played by Sigourney Weaver destroyed the ship, escaping in an escape pod, unfortunately with the creature on board. She pushed it from the ship, and signed off duty.