More than one 'black goo'?

I think the Black Goo is alien (Xenomorph) DNA, and that is all. Everything it comes in contact with becomes some hybrid or version of the XENO. Even Cuddles who was 'aborted' ends up as basically a huge facehugger, and 'mother' to The Deacon. I think the Engineers obviously revere this creature as 'the perfect being' (or maybe the perfect weapon) and the shrine (murals) suggest it's really all about THE XENO. (The one mural also shows the Alien creature at the side of the Engineer, head bowed, like a perfect Pet) I've used this before, but the original title (after 'Alien Genesis') was 'Alien Engineers'. Now- why they want an entire planet full of XENO type creatures- i do not know! I also believe the substance in the opening scene was completely different than the black goo. It looks/ behaves NOTHING like the Black Goo. (This doesnt explain why cargo hold doesnt leak- sorry.)

I believe this is very much the case this deleted scene shows. http://youtu.be/ieXvjFH8oYg Although it is the opening scene, it shows that it was a sacrifice. So the way the substance altered him is different than the other substances on the ship. BUT this does not prove it beyond a doubt. The scientist only was given a drop and then inseminated a woman afterwords, so could just be a effect of the dose and transmitted to fetus in that case. Another thing is, I assumed that the alien the biologist was attacked by was mutated from the worms you saw them walking on in when the entered area with the canister.

Yup. The Hammerpede is definitely a mutated earthworm.

LV223-worms or dirtworms :) I also think the fact no Xeno came out of the biologist backs up the idea of more than I 'Goo'. The only thing is if it is canon, Queen laying eggs would suggest the Xeno species was created by a 'sacrifice' of a Engineer.

Excellent ideas, and great first post. I think you`ve possibly filled in something that`s been bugging me with this relating to how the weapon is combined. I really believe the goo must be meant to be combined and that while handling the urn and opening the inner glass part David had a little of each on his finger. Creating the mixture from the completed weapons in the urn, so you can see the specks that are almost suspended within the drop... The Deacon may very well be a hybrid creation that has a slightly different nature, because its genetics have borrowed traits from the black goo. And when the black goo is combined with the Alien genetics the goo`s effect is altered, the goo itself borrows traits from the alien genetics... There`s definitely a back and forth, some mixing going on imo. It`s how they are combined in different ways, and in different ratios that created the different effects of the combined weapon... and the size differences ;) There`s always a third variable, or element in the mix that allows for the combination of each in different ways, which is what ive currently been trying to stress. You really could be correct, and somehow they combine all 3 and there are more effects we have yet to see... But the engineers may not have known the dangers of somehow combining all 3, and didn`t leave data about any additional effects before they died, passing on their knowledge to Weyland corp. Who could only translate it up to a certain point of certainty. And they only left data on two types of effects... but I`m thinking at least 2 forms. Probably more... The ones we`ve seen, they both morph things... destroy and rebuild them in a new form. The clues we need to see lead to a strong probability that the Deacon may be equipped with some sort of enhanced form of the ability to morph things. Some form of the morphing life-cycle, but i`m not really expecting egg morphing. One effect the Deacon may create breaks things down at a genetic level, recombines them with the alien genetics, and uses the combination of the alien genetics and the black goo to rebuild the organism into something the Deacon can use. Another creation of its own image... The creature that is subdued is morphed completely into another Deacon, and the first becomes a servant or the second a servant for the Deacon original. This would happen because of the combined effects. This is why the word Deacon has a meaning the implies one of two agents of sorts. Morphing people directly, perhaps, like how Fifield`s genetics were being overwritten by the Aliens.. The Deacon may be the forerunner of Royalty and destined to serve... The one it spawns when it meets someone, or a dead body it can use, becomes royalty.

If all that has been mentioned about the goo..mixing various combination would yield a myriad of results..you would think at some point that the Engineers would be afraid,,very afraid to use,,or even handle the goo. Send their entire collection of goo..on a spaceship directly in to their fires of their sun...or a another distant star,,for it's destruction.. Not only was it a WMD for humans,,or other seeded planets..but also themselves. Eliminate the threat and move on to another method to control the growing species they cultivate.