If the goo essentially serves as a starting point for an alien lifeform, why is the planet that the Covenant lands on completely devoid of life?
So, David lets the liquid loose and it obliterates all of the Engineers in seconds. Later in the film, David is discussing that nastiness he unleashed on those baldies and he makes it known that the ooze will find a host and incubate until it has grown large enough to ditch the host and emerge a big bad, independent alien, or, after said point, to produce pods for larger, other alien species to soon be born (in the form of the facehugger), before repeating the entire process and eventually blossoming into a larger Xenomorph.
So… where are all the aliens?
Were there only the hundred or so Engineers we saw killed on the entire planet? If so, why does the environment seem to be thriving so? Has David been watering the lawn? Surely someone was on that planet that inadvertently helped David to conduct his countless creative experiments. Elizabeth Shaw’s body alone certainly didn’t make that a possibility.
Where the hell are all the aliens? Where are the remnants of the lifeforms – other than the Engineers – that once called that planet home before becoming hosts for a superior predatory lifeform?
How… in the world… did that entire sequence… work?