Black liquid and the Engineers immortality

I'm speculating, but based on what we've seen there are two kinds of mioengineering going on in this film... I think the Engineers found there was no secret of immortality, just more efficient ways to cheat death. I'm guessing that at some stage they found a way to reduce themselves to this black liquid. That the 'invitation' is a con, they need us to reform in some way... When we come along one crew member has his suit compromised by the black liquid, this starts to alter him into an Engineers body, some kind of recoding of his brain must happen to get him to do certain things, but i woldnt be surprised to see a giant blue guy emerge from whoever is infected. Then there is the technology that they invented, and aren't aware we have taken back to the prometheus. This technology has a white motif, as opposed to the blackness of the engineers. A yin yang motif. This is what David has played with. It uses the little eye splinter worm and all sorts of other things. Probably wrong on some of the details, but i think there are 2 distinct processes at work in the film, and we come along and mess things up. I think the urn room is nothing more than all the species the bighead has created, but whereas there was a blue mist in Alien, i think the black liquid is alerted in some way by our presence there, and strikes quickly. i think this ties some of the ideas of the movie together, why we were so wrong, every king has its reign, the invitation, why there are so few engineers, why squiddy is pinky white, and i don't think were going to see a typical chestburster, i think he has to do something slightly different, but has a nod to the host as incubator for another being transforming.