What Is the Offspring in Alien: Romulus? The Alien Series’ Newest, Most Nightmarish Hybrid Creature Explained

Warning: The following article contains major spoilers for Alien: Romulus.

The Alien film series has seen its fair share of truly horrifying creatures even beyond the Xenomorph, and Romulus has brought yet another ghastly entity for us to squeamishly gape at: the Offspring. But just what is this strange new alien hybrid? Here’s our attempt at an explanation.

What Is the Offspring in Alien: Romulus?

Between all the acid, death, and yonic wall imagery, it’s easy to miss some of the lore Alien: Romulus spouts, and you’d be forgiven if you were left a little confused by the Offsping’s presence, as cute as it is.

Simply put, Alien: Romulus’ Offspring is a baby human/Xenomorph hybrid creature seen during the film’s end sequence. It’s a nightmarish, gangly spectacle birthed by the character Kay Harrison after she injects herself with a questionable and experimental mutagen sourced from a Xenomorph. Meant as a trigger for human evolution, the mutagen quickly transforms the already-pregnant Kay’s fetus into the grinning disaster we all now know and love, played by 7’7” former college basketball player Robert Bobroczkyi (yes, the Offspring in Alien: Romulus is actually portrayed by a real, physically present actor).

Alien: Romulus and the Offspring’s Connection to Prometheus

The Offspring itself is a neat little nod to Alien: Resurrection’s somewhat goofier attempt at a human/alien hybrid, but it also follows some deep complex lore laid out in the Alien prequel films Prometheus and Covenant. The black goo mutagen found in Romulus (and ultimately injected into Kay) seems to be a kind of reverse-engineered form of Chemical A0-3959X.91-15, the primordial black goo created by the Engineers (aka Space Jockeys) that both created life and acted as a bioweapon.

In Prometheus, we see that the black goo works as a pathogen and can either violently mutate those it comes into contact with, with horrifying results, or impregnate a host with a parasitic organism. Similar to Kay’s rather disgusting birth scene in Alien: Romulus, Dr. Elizabeth Shaw in Prometheus is impregnated by one such creature, dubbed the Trilobite, though that creature was much more squid-like than the Offspring, showing there can be a wide variety in hybrid creatures created by the black goo. Those hybrid creatures resulting from birth then attach themselves to a host, which subsequently gives birth to another hybridized creature possessing Xenomorph qualities.

In Alien: Romulus, the battered android Rook explains that the scientists aboard the Renaissance Station (where Romulus takes place) were able to synthesize a version of Prometheus’ distilled primordial ooze, which Rook calls the Prometheus Strain, by extracting fluids from a Xenomorph. According to Rook, humans are not fit to colonize space and so the Weyland-Yutani corporation is seeking to use the experimental mutagenic ooze to evolve humans (read: their workers) into the ultimate life form based on the Xenomorphs’ extreme adaptability. From experiments on rats, we can see that the mutagen has an incredible ability to heal, though we later also see that it eventually transforms and kills the host.

Enter Kay who, grievously injured, is eventually handed some vials of the mutagen to take back to the scavengers’ ship, the Corbelan, and told to get herself into cryostasis. Fearing she may die from blood loss, Kay injects herself with one of the mutagen vials, which immediately closes up her wound. She makes it back to the ship and situates herself into a cryopod, but things aren’t all good as her belly rapidly swells, and she quickly, gruesomely gives birth to an alien egg containing the Offspring. The Offspring then grows into a tall lumbering human/Xenomorph hybrid that looks uncannily similar to the overbearingly pale Engineers as seen in Prometheus and Covenant.

As to why the Offspring in Alien: Romulus looks like an Engineer is a bit of a mystery. But it does seem to provide an implicit confirmation that the Engineers are the progenitors of human life and, perhaps, humanity in its ultimate biological form.

Whether or not the Offspring will return for a repeat appearance in the Alien franchise is anyone’s guess, but I’m sure we can look forward to its ramifications in future Alien installments.

Alien: Romulus is now playing in theaters.