Board Thread:Theories and Speculation/@comment-25302335-20150914182027/@comment-4912646-20150918141118

Here's some text from Hamura's databook entry (courtesy of translator Organic Dinosaur) that negates a lot of the alternate theories that have been thrown around:

Hamura became the head of the Otsutsuki clan after the battle. In order to stand guard at the sealed Jyuubi’s essential body (/vessel), which is the Gedou Mazou that was produced by the “Rikudou Chibaku Tensei”, he and his clan migrated together towards the moon.

So the statue was without a doubt created at the end of the brothers' battle with the Ten-Tails, meaning its chakra had to go somewhere (into Hagoromo), and then Hamura departed for the moon while still young, as shown in The Last. The Last showing the whole beast going into Hagoromo therefore must be a mistake, likely because the people making the movie didn't know how to handle this contradiction any better than we do.

This doesn't explicitly deny the possibility that Hagoromo summoned the statue in order to survive extraction and then de-summoned it, but it does 100% deconfirm the old story about Hagoromo extracting the chakra from the husk and creating the moon at the end of his lifespan.