The Doctor links to the Memory and discovers that it was created by the corporations who created the crabs to fight in their war, and since the corporations abandoned the planet it has been being eaten by the local marine life. It reached out for Peri, desperate for a personality to hold itself together. The link to the Memory also allows the Doctor a connection to Ranger, from whom he learns that the crabs were prisoners of war, who had their brains transplanted into crab bodies to help fight the war. When Ranger's sister was similarly altered, Ranger feared for his own life and escaped to the beach.