17. Baby Xenomorph ("Alien: Covenant," 2017)
For some reason, "Alien: Covenant" does away with the brand of Chestburster we've been seeing since 1979 and instead adds this guy: a very small version of the fully grown alien. He then does a bit of yoga with his creator, implying an intelligence to the alien we don't usually see. But it doesn't change that a little, kind of cute version of the alien is a terrible idea for a movie that's supposed to make the monsters scary, to say nothing of retconning one of the most disturbing scenes, and creatures, ever to appear on film.

16. Newborn (“Alien: Resurrection,” 1997)
“Alien: Resurrection” resurrected the franchise by bringing Ripley (Sigourney Weaver) back from the dead. In doing so, it mixed her DNA with the aliens, resulting in this goofy abomination. It acts like a baby — but it’s murdery! So weird, right? Luckily this nasty looking but entirely not scary little guy gets sucked out a tiny hole in a spaceship and turned into goo immediately after being born.

15. Hammerpede (“Prometheus,” 2012)
It’s not a facehugger, it’s a snake-like wing-faced creature that just looks and acts a lot like a facehugger in “Prometheus.” This dopey goo-eel seems easy enough to avoid and only dangerous if you’re a complete idiot. Unfortunately, some of the characters of “Prometheus” are exactly that.

14. Deacon ("Prometheus," 2012)
Another weird alien variation added in “Prometheus.” Apparently separate from the Neomorph seen in "Alien: Covenant" is this little blue guy, born from the Trilobite and an Engineer. He vanished in the space between movies and never did anything scary.

13. Fifield Mutation (“Prometheus,” 2012)
Apparently if you get attacked by a Hammerpede and then infected with black goo, you turn into some kind of melty skull-faced maybe-xenomorph that then has superhuman strength and jumping ability and is incredibly hard to kill. Fifield, like a lot of “Prometheus,” makes no sense, and this one-off contextless monster is a weak addition to the lineup.

12. Trilobite (“Prometheus,” 2012)
It’s hard to follow what’s going on with “Prometheus,” the black goo at its center, and the various creatures that black goo creates. But one result is the Trilobite, a cross between a squid and a facehugger. It’s not too impressive even when it’s huge on account of it just looks like a big rubber-and-CGI catch of the day.

11. Predalien (“Alien vs. Predator: Requiem,” 2007)
The alien that results from a facehugger implanting its embryo in a Predator is a hulking version of the xenomorph. It’s not really more or less frightening than any other alien, except that it can directly implant tons of its gross embryos in a person’s throat. It’s mostly just disgusting.

10. Dog Alien/Ox Alien (“Alien 3,” 1992)
“Alien 3” is generally considered a weak sequel because it feels like a major step back from the interesting progression achieved between “Alien” and “Aliens.” That goes for its alien, too, which, depending on which version you watched, either pops out of a dog or an ox and comes out quicker, but smaller and less menacing than previous iterations.

9. Spineburster ("Alien: Covenant," 2017)
Though it's not significantly different from several other sorts of alien "-bursters," something about the way neomorph is born adds a fresh element of "ugh." The way it shreds its way loose with its sharp, spiny back forces the audience to think of all new kinds of "Alien" birthing pains.

8. Neomorph ("Alien: Covenant," 2017)
The prototype xenomorph that's a big star of "Alien: Covenant" manages to hit on a different kind of creepy from its jet-black cousin, with the neomorph's weird human-like skin and lumpy body. Its vicious teeth and over-the-top aggression also set it apart, but its willingness to run straight at its victims' face isn't nearly as unsettling as the idea a xenomorph could be hiding somewhere in the shadows, waiting for you.

7. Xenomorph (“Aliens,” 1986)
In James Cameron’s sequel to the original “Alien,” the creatures got a “name” and a bit of a design change. The aliens in “Aliens” are more like soldiers and plenty of them get dispatched by machine gun fire. But their ant hive-like single-mindedness still make them pretty scary, especially as they manage to utterly ravage movie’s marine force.

6. Bellybusters (“Alien vs. Predator: Requiem,” 2007)
The “Alien” franchise’s xenomorphs have made it to Earth precisely two times: in “Alien vs. Predator” and its sequel. “Requiem” gives us one especially horrifying addition to the franchise: alien embryos deposited down the throats of pregnant women that turn them into something akin to spider eggs. It’s as awful as you’re imagining.

5. Smart Aliens (“Alien: Resurrection,” 1997)
There’s a lot of weirdness going on in “Alien: Resurrection,” which jumps in the “Alien” timeline another 200 years from “Alien 3,” but it does get one thing right. The aliens in the movie are highly intelligent, setting traps for humans and even affecting their escape by sacrificing a weaker one of their number to use its acid blood to burn a hole in the floor of their cage.

4. Queen (“Aliens,” 1986)
James Cameron’s follow-up to “Alien” was brilliant in the way it took a completely different tack from the original, while still managing to be scary. But nothing was more frightening than the enormous, obviously intelligent, shockingly powerful Queen Alien. It was like a T-Rex ravaging around the hangar of the Sulaco.

3. Facehugger (“Alien,” 1979)
The very first creature ever seen in the series is small but explosively violent. A strange spider-like shape and a stranger method of attack in going for the face, the Facehugger’s somewhat unassuming nature makes it all the more terrifying. It’s an insect-like parasite, which makes it shudder-inducing both for being scary and for being straight-up gross.

2. Chestburster (“Alien,” 1979)
Though the “Alien” franchise and creature has been refined, and in some ways, made spookier since the original film, there’s still one incredibly horrible scene that has yet to be topped. That’s the infamous death of John Hurt’s character Kane as a baby alien tears its way out of his chest. There’s nothing in the “Alien” universe that’s quite as horrific.

1. Big Chap (“Alien,” 1979)
The original H.R. Giger creature in Ridley Scott’s sci-fi horror masterpiece stands apart from all the future versions of the monster — specifically because he’s so impossibly alien. The creature has a hint of a human-looking skull hiding under its smooth domed forehead that a little extra uncanny weirdness.