Board Thread:Naruto Discussions/@comment-3279282-20140828133937/@comment-24593592-20140901112654

Elveonora wrote: Seriously... the rabbit IS Kaguya. The Tailed Beasts aren't 100% of the Ten-Tails chakra. Had Hagoromo separated all of her chakra, Kaguya would have died. The rabbit is what remains in the body when you take away the portion of her chakra that the Tailed Beasts have. You could say it's the "tenth" tail so to speak.

I believe the rabbit is Kaguya's will that merged with the Shinju/Gedo Mazo. Kaguya may have died and lived on as chakra, possessing the tree as Obito did Kakashi.