Massive plot hole or did I miss something?

Good question. I think the amount of black goo is an important factor. Im not an expert, so maybe im not right. Ín Prometheus, in the opening scene an Engineer drink a lot from this liquid, and it broke his dna spiral to components. But if sby drink/ connect just a small amount of black goo, it start to mutate the organism. 

But im just guessing, not sure im right. 

That's true, but I speak of the scientist Fifield who faceplants the black goo a and ends up a mutant. According to Covenant lore he should have died like the Engineers.

That's true, but I speak of the scientist Fifield who faceplants the black goo a and ends up a mutant. According to Covenant lore he should have died like the Engineers.

Hm... You are right. Well, hopefully here are some better scientist, who can answer :-)

Well, i read now some info about that, because im also interested in this question.

As i mentioned before, i think the amount of black goo is important, and there are difference between the inhalation and the ingestion. Maybe fifield just inhalaled it (??), thats why he mutated. Holloway drank that, and if i remember well, he didnt mutated. 

But at this point i have another question. What happens, if the black goo connected with skin... Because thats what we saw ín the Alien Covenant... And im sure, fifield's skin also connected with this materia. I dont know... 

And why couldnt we see any neomorph or any mutated non plant life? I think, because they kind of extint... They didnt have any eatable animal. So just their sexual organs (spores) could survive, waiting for a new host. Maybe it's because their life cycle. 

But im just guessing. Maybe im absolutely wrong. 

I just cant understand why people are asking these questions since 2012. The answer should be as obvious as it can get?!

They are called engineers, right? They mastered biomechanics, genetic engineering, nanotechnologie etc. The black goo simply is a device - i guess something like a virus. And viruses do different things. A hep c virus does one thing, a ebola virus does another thing, a h5n1 virus does another thing. The black goo at the beginning of prometheus was programmed by the engineers to dissemble dna. The black goo on lv223 was programmed to mutate dna and the black goo in the AC bombing was programmed in still another way, maybe to petrify on first contact. Thr urns in AC exploded in midair, the urns in prometheus just started leaking, they didn't explode. Obviously the programming was different. It's as simple as that.

i think it is a really good question and to my knowledge we dont have a definitive answer, yet.

We thought we had a good idea after Prometheus yet i consider myself a fan of the universe and i dont 100% know for sure how it works.

I would suspect the goo on LV223 - regarding Fifield and the worms was the same goo that deployed in a:c

Why?

Well David and Shaws jugganaut came from LV223. So you would think it had the same compounds? The goo was loaded on the Jugganauts as a bio-weapon.

I think the amount of goo counts, the way it is ingested counts and also how much is ingested.

It is also possible that you are right jdvyne and that there are different types of goo but i dont think we can say for certain that this is the case????

It's is about the amount, as well as where it comes from. The goo David infected Holloway with came from the glass container he had to break the top off of (which I don't remember if he took that our of the urn). And he only put a tiny drop of goo in the drink. This caused him to slowly mutate ending when he was hit with the flame thrower.

Fifield fell into goo that melted his helmet into his face, and looked like he couldn't breathe, so he probably ingested it causing him to mutate faster.

The urns released in AC were programmed or something because they swirled around releasing the goo, which also swirled in the air like it was mixing itself before falling. When it hit the "engineers," did it look like they were all sort of "sprouting" appendages or something like that as they turned black and charred looking? Maybe the amount that hit them would have mutated them but instead worked so fast it outright killed them.

I agree with jdvyne, it is all in the programming. 

It wasn't programmed to turn Engineers into agressive alien creatures, maybe it is a failsafe mechanism, who knows?

Lol with the people who 'know' what the black goo is! Not even Ridley knows what the black goo is exactly. It's : "What ever they need to further the plot type goo" . The goo is exactly the same as everything else in Prometheus and alien covenant : vague not thought through... no bodies at the steering wheel general wtf type stuff!! They should of sat down and written exactly what it was from the start... with the whole universe they created. Not make it up as they go along in a pub Just before the shoot type film making... :S

And to three original poster: yes Ridley did say the black goo destroys the 'meat' only leaving behind the plants etc.. why they hate the animals and not the plants is anyone's guess! Also if it wiped out the insects how are the plants (which need insects and birds and some animals in some cases to survive) still alive after 10 years hmmmmm...pretty odd.

In Alien: Covenant, David describes the black goo mutagen thusly:

"The pathogen was designed to affect all non-botanical life forms... all the animals... the 'meat', if you will... either kill them outright or use them as incubators to spawn a hybrid form... highly aggressive."

"The pathogen took so many forms... and was extremely mutable.  Fiendishly inventive in fact.  The original liquid atomized to particles when exposed to the air."

@Ripleys_Ghost - Bingo!

Yep, safe to assume direct contact with the pathogen will always affect the host in a different way depending on how it is consumed or how they came in contact with it. Very interesting thread nonetheless!

The reason is possibly an overdose of the pathogen/black goo.

In small amounts it causes mutations but in extreme quantities it causes the body to petrify/decompose.

The same can be observed in some examples:

Engineers sacrificial scene Prometheus:

medium dosis = body decompose

Prometheus, Fifield,Holloway:

Very small dosis causes mutations

Covenant, David's black goo bombing:

Amount dropped is massive. Bodies of lifeforms cant absorb that amount and just straight decompose/petrify. The obsolute amount ingested through the air should be the same like in the Prometheus opening scene or maybe more.

Covenant, the two victims which ingested the spores:

Very small amounts. It causes mutations.

TL/DR: The pathogen amount dictates the outcome.

Programming the black goo in certain ways is not necessarily mutally exclusive with it having different effects dependent on how it is consumed.

But I think surely that different programming of the black goo is the most obvious explanation. Just like with a computer. Inside you have a cpu and for example a memory space. The components are always the same but it can do very different things dependent on the programming that lies in the memory space. The cpu could operate a microwave, a selfdriving car or a missile defence system - you only need to load the programming on the memory space. The black goo as it is, is like the cpu and it does whatever is programmed into its memory space.

And David had lots of time to understand how the black goo works while on their way to Planet 4. At last he can operate the delivery system, maybe while on the way he changed the programming of the black goo. I could imagine, that on the "memory space" of the black goo (if it's something like a virus than of course its memory space would be its dna) there are several programmings saved and with the delivery system you can choose and activate one or the other programming.

The AC urns and the urns on LV-223 were surely of the same sort. But I guess they had a different purpose. The AC black goo should kill off all the meat whereas the LV-223 black goo should mutate present lifeforms. Could be the very same urns but the urns on LV-223 were simply running a different programming than the AC urns. That's my view on this topic.

David made it clear in Covenant that there were different varieties of the black pathogen and that it took many forms.

It was also clear that there were numerous varieties of the black pathogen in Prometheus. The Urns were even marked differently and there was a variety of different sized urns in the Juggernaut.

Someone really needs to ask Ridley. I'm guessing he's not exactly sure though.

Yes I understand all points as stated here and elsewhere. However are we saying that on Paradise there was absolutely no other non plant life forms than the Engineers? No birds, insects, reptiles, mammals or marsupials? If the Engineers are simply meat bags as some suggest, what about other life forms? At least one form of life ended up producing spore sacks. Whether this was flora or fauna is not known.  

Nice Replies here.... very valid Points..

A Problem is indeed it appears RS/FOX dont really have any Solid Idea for how the Black Goo Works, it was a bit of a mess but Prometheus was quite clear...  if Fans read Spaights Alien Engineers and the Nano-Scarabs and how they worked and replace them with Goo then its clear how it worked.

FOX saw that the movie was a bit vague and attempted to answer the Black Goo with a Weyland-File that contradicted a lot of what was shown in Prometheus.

Alien Covenant has completely Contradicted the Black Goo from Prometheus, and we are not just talking about the Dead Engineers here... but also how David has Urns in that Room that seem to not be leaking at all, yet this room is not a Secure/Sterile Room like in Prometheus.. David even has a Urn opened like he did in Prometheus but this Urn in Alien Covenant is not Frozen, and shows NO SIGN of activation at all.

do they know what they are doing?  Have they figured out and made a Plan for how the Goo works? Who knows... i would assume they have and they have changed how it works a bit from Prometheus. Will we see the Black Goo again?  I am not sure.

They needed to from Day One have a Plan for this and stick to it... like lets say this Plan for Aliens..

Eggs= Face Hugger = Xenomorphs

Xenomorph Queen (occurs under some unknown circumstances) and Lays Eggs.

Xenomorph Gestation takes on Traits of the Host.

The Black Goo was more Complex but they needed to have a idea how it worked... here is what i felt it did and this adds up to Spaights Alien Engineers

Sacrificial Goo = Breaks down Organisms DNA and reforms them into a Mutagenic Parasitic Chemical that reacts with the DNA of Organic Life it comes into contact with, the Organic Life that is exposed to this Chemical has its DNA Re-written where the Mutagenic Parasitic Chemical imprints the DNA of the Organism this Chemical was optained from... so that the Organism that is broken down to produce this Mutagenic Parasitic Chemical  has its DNA imprinted onto other Organic Life it comes into contact with while also Evolving the Organic Life-forms best Traits.

The Black Goo therefore was obtained by Something Related to the Xeno-strain DNA being Sacrificed to Produce the Mutagenic Parasitic Chemical stored within the Urns.

Example....

Wolf + Sacrificial Goo  = Wolf DNA Mutagenic Parasitic Chemical 

Which could be collected and stored into Urns... or if the Sacrificed Wolfs broken down reaction is not collected into Urns it would just be spread around into the Air or into the Water.

Either-way this Chemical Wolf DNA + Human Contact would create a Hybrid that would be similar to a WEREWOLF

Now i have got that out of the way... Alien Covenant it appeared to have a different effect, i have no real explanation for the Urns in Davids Lab (or other things as there is a lot of Plot Holes) that simply wondering have these Urns simply over time lost their effects and thus are Safe? Could offer a explanation, and so the Environment of the Juggernaught and LV-223 Outpost kept them in some kind of Sealed/Stasis.

What i can speculate about is WHY those Engineers are not effected like in Prometheus...

The only Explanation that makes sense to me (but some comments on here could also apply) is that the Urns are like a Nuclear Weapon

They have a number of components/layers and a Nuke has a Plutonium Core  (or Uranium)

If someone comes into contact with Plutonium/Uranium depending on exposure and type of Compound. But it would usually damage Organs of a Human, even Cause Cancers and also may lead to Mutations.

But contact with Plutonium/Uranium does not explode or severely burn the Body.

But when Plutonium/Uranium is used in a Nuke and Weaponized/Activated it causes a Massive Expostion which Burns all Life within a Radius to nothing, as the distance from the epicenter is increased then victims bodies suffer various forms of being Burnt, the more mild the further away.

At a Large Distance away we see other Radioactive effects instead such as Damage to Organs, Cancers and Mutations of Cells.

I think maybe the URNS act the same way and that when they are Weaponized/Activated as Planned, the Primed and Dropped URNS Explode and the Black Goo effect is thus different compared to just coming into contact with the Radioactive Materials that make up a Nuclear Weapon.

This is the best most bullet proof explanation i can come up with ;)