Deacon already around? Contamination? Atmospheric hole?

[The_Foxcatcher]

But my favorite theory is still that they had captive Ultramorph/s to derive its DNA and brew the Black goo. It killed them all...

Sure Fox, we are presenting our favorite film theories about what killed the Engineers in the 2000 year old LV-223 disaster.
With the small amount of information with have, yours is certainly possible.

I feel that the holes on the cyrochambers was just an overplayed idea with no logical implication.  Because, If the engineers were chest bursted, and if the chestbursters broke the way out of the glass, there would atleast be dead Engineer bodies inside the cyrochamber. But they were empty.

That leads to a question; Why did the 3 stasis chambers with holes in them look empty?
- One possible theory is that the bodies of the Engineers had completely decayed.
The Engineer ship might have had air that was moist which also contained bacteria.
And in 2000 years the bodies of the dead Engineers exposed to that air completely broke down.

Here is a discussion of how a body, including bones, could completely decay.

If a body is exposed to water, insects, open air, or highly acidic soil, then bacteria and fungi will be able to invade that porous network, and seek out the proteins of the collagen within the bones, which causes those bones to break down and eventually crumble to dust!

However, if a body is buried in a warm, arid climate, it is must more difficult for bacteria and fungi to survive, which makes it harder for traditional decomposition to occur. In humid conditions, bones might be broken down in a matter of a decade or so, but in a dry climate, it could take thousands of years!

https://www.scienceabc.com/humans/skeleton-mystery-dont-bones-decay-decompose.html

Also, there's no indication from Alien franchise that a Xenomorph / Ultramorph would implant (impregnate) something inside hosts. Only face hugger does.

Sorry, I'll be more clear about that.
- Let's forget about my theory about the Deacon impregnating a host, since there is no clear evidence of that.
- However, what I meant about the Xenomorphs is that they could bring an egg to a victim and then the facehugger could do its thing.
Xenomorphs can move eggs around.

Other Xenomorphs also tend to the Eggs once they are laid, moving them from beneath the ovipositor to "nursery" areas within the Hive.

http://avp.wikia.com/wiki/Egg_sac

* On another related topic; In the beginning of "Alien 3", how did the eggs get on the Sulaco?
My favorite theory about this is that the Queen carried the eggs there.

So most likely it's possible that in some different pyramid, the Engineers were making and storing face hugger eggs (like the cargo of derelict bomber ship in Alien). And that those face huggers somehow came out by having accidentally disturbed. Some of the engineers got face hugged and some of them got killed by those adult chestbursters.

I like that idea.
- My favorite theory about this is that every room in the dome/pyramid that the crew explore in the movie is not completely shown.
Xenomorphs, Deacons / eggs could have been kept in hidden parts of that place.

But let's wait for Covenant. It's surely going to shed some light on this.

Yeah. I just have to be patient since in the US, AC opens on May 19.

Hi BB-15!

I will wait for you to see Covenant and am very much eager in discussing the film with you.

Btw, I saw Covenant and it doesn't shed any light on what were the Engineers running from in Prometheus.

[DorkiDori]

^^^ DOOD! SPOILERS TAGS!!! The US doesnt get Alien Covenant until May 19th!!

[bb-15]

BASIC SPOILERS FOR AC!!!!



SPOILERS




SPOILERS




SPOILERS

Hi BB-15!

I will wait for you to see Covenant and am very much eager in discussing the film with you.

Btw, I saw Covenant and it doesn't shed any light on what were the Engineers running from in Prometheus.

Hey Fox; yeah, I'll see AC on 5/19.
I've pretty much avoided spoilers for the new movie but I saw a Rotten Tomatoes summary which stated that AC does not break any important new ground in the franchise.
It seems Ridley did AC for those fans who wanted a more straight forward Alien film.
Scott is a flexible guy.

Anyway, no more discussion/spoilers of the plot for AC with me until a week from today!

[D. Compton Ambrose]

They got a captive Ultramorph/s on LV 223 - To extract its DNA to brew the black goo. The Ultramorph/s broke free somehow and resulted in the chaos. It/they killed all the engineers one by one.

I think you are half-correct. It seems to me that what is happening is they are running from the pathogen, as it is being carried by a breeze and entering their bodies via airborne transmission. I also think that this so-called ultramorph/ultimate being has been - much like the Queen Mother in the comics - infiltrating their minds from lightyears away for millions of years, indoctrinating them into worship, and servitude to the ultimate end goal which would lead them to the accelerant... which it has transformed into at will.

Ergo, the accelerant is the Ultramorph. It is a shapeshifting omnipotent, sentient killer space entity that can become solid, liquid, gas or energy/wavelength at will. Which would explain why it only creates mutations randomly, or when it feels like it. It could also be what drove David to have such a god complex - as he inevitably exposed himself to its manipulation by studying the ways of the Engineers heavily dogmatic and zealous theocratic writings and customs (which they in turn developed via unconscious exposure to the Ultramorph, and the downfall of their civilization out of their vainglorious obsession with the new "holy biotechnology" they had 'unlocked', and then David after them) so it all comes full circle when you realize the creators are - ironically - the fallible, and the creations the infallible retaliation against them by the original creator - mother nature, God, the Universe - as an equal and opposite reaction that is destined to occur when such a disturbance occurs against the natural order of things. And so it all goes on and on and on because the Alien is effectively the physical manifestation of insanity.