How many of you simply digested the end and went home all done?! ***Spoilers***

The emergence of an Engineer-Xenomorph Hybrid Baby was a flawed inclusion and felt like a desperate attempt to tie the film with Prometheus.

The Black Goo does not contain Engineer DNA. It was originally manufactured by the Engineers on LV_223 as a bio-weapon, using the DNA of the Protomorph (the creature depicted on the mural). The Black Goo mutates infected hosts, imbuing them with the Protomorph's predatory attributes.

The Protomorph is the original creature with the same life cycle: Egg, Facehugger, Chestburster, Adult (as illustrated on the mural), and is the progenitor from which other creatures, like the Xenomorph, evolved. Every time a Facehugger impregnates a host, the resulting embryo adapts to the DNA of the host, carrying some of its characteristics—like the Runner in Alien 3 adapting to the DNA of a dog.

In Alien: Covenant, David used the same Black Goo to mutate cross-bred insect eggs, eventually creating the Xenomorph. The Black Goo also mutated fungi into spore-producing mushrooms, which impregnated hosts with Neomorph embryos.

And now, in Alien: Romulus, we have Rook deriving Black Goo from Facehugger blood, which then infects a pregnant woman, resulting in an Engineer Hybrid!

It's simply laughable—if not downright ridiculous!

I see it as a lost opportunity. A version of the Ultramorph (a concept designed for an early draft of Prometheus) or the adult version of the Deacon could have been far more consistent and logical, while still being terrifying and unique.