As "Alien" fans know, the xenomorph has acid for blood, is a relentless hunter, breeds parasitically inside human hosts before killing them, and has a tremendous hunger for cash. It's eaten up some $1.4 billion in earthling movie-ticket money over the past 38 years and seven films. And Fox is hoping it will gobble hundreds of millions more when the eighth film, Ridley Scott's second prequel "Alien: Covenant," is released May 19.

Over the years, Moviefone has learned a lot of wonderfully disgusting facts about the franchise (read this if you want to know what the alien's innards and mouth-slime were made of, or this if you want to know how Lance Henriksen nearly chopped Bill Paxton's finger off performing his knife trick), but in honor of "Alien: Covenant," we've dug up a few more things you didn't know about the scary space series.

Alien (1979)Directed by Ridley ScottShown: Sigourney Weaver1.Sigourney Weaver was an unknown when she auditioned for "Alien," but that anonymity proved an asset. "We felt that if Ripley was a big name, she would lose part of her mystery," producer David Giler recalled in 1991. Weaver claims she got the part because 20th Century Fox studio chief Alan Ladd Jr. showed her screen test to his secretaries, and the ladies gave her audition the thumbs-up.

2. Weaver earned about $30,000 for the first "Alien," $1 million for "Aliens," $4 or $5 million for "Alien3" (plus a percentage of the profits), and $11 million for "Alien: Resurrection."

3. A scene cut from "Aliens" might have explained how Ripley developed her maternal urge to protect the orphan girl Newt. In the scene (above), shortly after she's awakened from her decades-long sleep, Ripley is shown a picture of the daughter who was ten when she first left on her mission, and who has since grown old and died. The prop was actually a picture of Weaver's own mother. The studio reportedly trimmed the scene because it slowed down the movie's pace and delayed Ripley's return to space.

4.David Fincher disavowed 1992's "Alien 3," even though it was his feature directing debut. "A lot of people hated 'Alien 3,'" he said a decade later, "but no one hated it more than I did."

5. Weaver said she felt that Fox had undermined the first-time filmmaker, first by having him start shooting without a finished script, then by micromanaging him. "They started off telling him they wanted 'Hobbit in Space,'" Weaver recalled. "Midway through, they're saying they want an E-ticket ride of a movie. It was a mess."

6. Similarly, Joss Whedon disavowed 1997's "Alien: Resurrection," even though he found it a fairly faithful adaptation of his screenplay. "It wasn't so much that they'd changed the script," he said in 2005. "It's that they just executed it in such a ghastly fashion as to render it almost unwatchable."

7. In the early 2000s, "Aliens" director James Cameron was working on an origin-story prequel -- the germ of the idea that eventually became "Prometheus," -- but he abandoned it when he learned Fox was developing the "Alien vs. Predator" crossover films. To this day, Ridley Scott claims not to have seen the two "AvP" movies.

8. "Alien vs. Predator" director Paul W.S. Anderson claimed that Arnold Schwarzenegger had agreed to appear in a cameo in the 2004 film as Dutch, his character from the original "Predator," on the condition: that he lost the California gubernatorial election, which he did not. Also, Anderson said, Schwarzenegger had wanted to film the cameo at his own house.

9. In 2012's "Prometheus," when the snake-like "hammerpede" alien bursts forth from Rafe Spall's corpse, Kate Dickie's screaming reaction is real and spontaneous. She didn't know what she was about to see: the sudden emergence of an alien puppet manipulated by the director. It was the same exact technique Scott had used to scare the actors in the original "Alien" when they first saw the "chestburster" force its way out of John Hurt's torso.

10. To create the sounds made by the glistening cave's ice crystals, the "Prometheus" sound effects artists used Pop Rocks candies, sprinkling them on hard surfaces and then spraying them with water to make them crackle.11. Originally, the filmmakers sought Max Von Sydow to play ancient tycoon Peter Weyland, but they went with Guy Pearce instead in order to be able to show the character as both young and old.

12. The old-age makeup Pearce wore in "Prometheus" took five hours to put on and another hour to take off. In character as the younger Weyland, Pearce appeared in a short promo clip, supposedly giving a TED talk in the year 2023. The clip, directed by Luke Scott (Ridley's son), marked the first time the TED curators had licensed their brand to makers of a fiction feature.

13. There was much talk, as recently as summer 2016, that Weaver and "District 9" director Neill Blomkamp were moving ahead with a fifth Ripley movie, one that would have pretended that the third and fourth movies never happened and would have kept Newt and Corporal Hicks (Michael Biehn) alive. But in April 2017, Scott (who would have executive-produced the Ripley movie), said that Blomkamp had never written more than a 10-page story pitch, and that Fox had nixed the project.

14. "Alien: Resurrection" went through many drafts, especially in regards to the film's climatic ending. At one point, Whedon wrote a draft where the Betty crashes on an Earth forest. Here, once she realizes they and the newborn albino alien are too close to a populated city, Ripley takes action. Armed with a grenade launcher, she flies around in a futuristic combine harvester vehicle to finish the newborn off in a very cool -- but ultimately too expensive -- sequence.