Growing up isnt easy. This whole story is a timeline of personal evolution the moon creature is the baby, Courtney the child, Clara the adolescent and the Doctor the adult. While Clara struggles to accept adult responsibility, Courtney takes her first steps towards independence. She falters as all young people do, alternately blustering ahead and creeping back only to step forward once more. She is testing the waters, deciding who to look up to and learning to trust herself. The moon creature signifies transformation. It springs forth from its protective shell, leaving behind its old world view for something new. Birth is a messy process. There is no growth without pain. The moon creature is unaware of the chaos it is causing, it is the innocent here. Clara must make the final decision whether this new life survives even in the face of the earths condemnation and she is not happy about it. She isnt sure shes ready to be the adult. Yet the Doctors faith in her does not waver.