You need to watch the scariest sci-fi movie saga ever before it leaves HBO Max next week

“In space, no one can hear you scream.” Terror in isolation is just as bone-chilling now just as it was in 1979 when the phrase appeared in the trailer for this sci-fi horror classic. 42 years later, those eight words still have frightening power in them. Just imagine it: A life-or-death struggle in the vacuum of space with no one to hear you, let alone help you.

While these films have evolved over the years (most notably into a more traditional, military action flick in the beloved 1986 sequel), the series is still best regarded as the foundation for sci-fi horror for both the 20th and 21st centuries.

The first four movies in arguably the greatest movie franchise to ever blend science fiction and horror — Alien (1979), Aliens (1986), Alien 3 (1992), and Alien: Resurrection (1997) — are the movies you need to stream before they all leave HBO Max on March 31.

In Ridley Scott’s Alien, Sigourney Weaver stars in the iconic role of Ellen Ripley, a crew member aboard the cargo ship Nostromo. A routine shipment mission through space is interrupted by a distress call to a desolate planet. The scouting crew, rebellious to Ripley’s orders to quarantine, return with a deadly parasite — known throughout the franchise and fandom as the “xenomorph.”

Ripley survives, but the horror is far from over. Thus begins a multi-film saga where the franchise’s protagonist somehow wakes up decades later, only for more aliens to reign terror.

The unholy acid-blooded creatures who chase and seek Ripley were chiefly designed by surrealist Swiss artist H. R. Giger, whose nightmarish aesthetic is a mix of mechanical, sexual, and macabre imagery. There’s even a term for it: Gigeresque. What makes the Gigeresque “Xenomorph” so special, though, is how it not only innovated in the then-rarely explored realm of sci-fi creature horror, but how its uncomfortably erotic aesthetic has ridiculous commercial appeal.

Alien was built on strong foundations, still standing over 40 years later thanks to Ridley Scott’s killer directing, a smart story of survival by writers Dan O’Bannon and Ronald Shusett, impossibly timeless production design by Michael Seymour (nominated for Best Art Direction at the 1980 Oscars), and a top-tier actress like Weaver (also Oscar-nominated, albeit for her work in the sequel) playing what was then a still-novel female genre protagonist. When Alien opened in 1979, horror movies had only just begun the “Final Girl” archetype with films like Texas Chain Saw Massacre (1974) and Halloween (1976).

Despite the unnerving nature of Giger’s designs (think: Satan but with an ‘80s punk phase), the Alien franchise is one of the most commercial film series in existence. These movies have grossed a combined billion dollars at the box office, while tie-in products like Alien action figures, keychains, video games, socks, and breakfast cereals are easy to find on Amazon. The xenomorph is a skin in Fortnite, and Disney is producing a new Alien TV series for FX with Fargo showrunner Noah Hawley. The world recognizes something in Alien, as if it’s rooted in our DNA.

But Alien has become more than its symbolism. As a series, it’s undergone a level of genre evolution few other film sagas ever have. The 1986 sequel Aliens by James Cameron is an adrenaline-fueled full-throttle action movie that eschewed the intimate violence of the first film. Alien 3, directed by David Fincher (who had such a nasty experience with 20th Century Fox that he disowned the movie in 2009) is a flawed but worthy allegory to the systemic abandonment of those suffering from the AIDS epidemic. Alien: Resurrection, considered the lesser of all four films, is ... well, look, it really is the worst one. But it’s still worth checking out.

But it all goes back to Alien, a movie that looks and feels as if it were made yesterday. More than 40 years later, Alien is still a giant in the science-fiction and horror space and is simply a fantastic movie, period. In space, no one can hear you scream. But in quarantine, your neighbors might.

Alien, Aliens, Alien 3, and Alien: Resurrection are streaming on HBO Max in the U.S. until March 31.