RinoZ
I think Formless One is an extension of the Spirit Nave, but in reverse, which is interesting. He gets power from the now, but with that he would become their eternal support, raising a communal weak species that needs numbers to survive into a communal species that could 1v1 the intelligent species and live. That's just terrifying. Good thing he is going the Paragon route.
If he choosed the giant grub, he would have been able to play with the larvae for at least six months. And with the reborn body he even had a chance to escape the pull of the ancients and overcome the pain while evolving. Not to mention the riches and fighting he would bring to the colony and its human inhabitants. 6 months holiday, think about it Anthony!