Spoilers ahead for the plot and ending of Alien: Romulus. Seven movies into the Alien series — nine if you count the Alien vs. Predator movies , and don’t act like you’re above it — we all have a pretty good idea of what the title characters look like.

There are the skittering Facehuggers, the tiny yet destructive Chestbursters, and finally, the adult Xenomorphs, sleek H.R. Giger-designed monsters described by Ash (Ian Holm) in the original Alien as “the perfect organism.

” Two mouths, one very long head, and a seemingly endless amount of slime. But devotees of the franchise know that there’s actually quite a bit of variety when it comes to aliens. Parasitic Facehuggers borrow a bit of host DNA for the Chestburster, which is how we got the dog-infused Xenomorph of Alien 3 .

And Prometheus brought a new set of weird little guys to the series, from the humanoid Engineers (not so little, actually) to the squid-y Trilobite. It’s no surprise, then, that Alien: Romulus doesn’t rely solely on the classic Xenomorph, introducing audiences to a brand new creation that’s also a callback. In the third act of Romulus , Rain (Cailee Spaeny) and her android brother Andy (David Jonsson) fight off an endless onslaught of Xenomorphs, while Kay (Isabela Merced) — the one other human survivor — makes her way to the stolen cryopods stashed on their ship.

Badly wounded and pregnant, she makes a desperate gamble for survival by injecting herself with a supposedly healing blac.