Star Trek’s Scariest Alien Monsters!

A spoiler warning graphic.

Spoiler Warning: There are spoilers ahead for the following Star Trek productions: The Original Series Season 1, The Voyage Home, The Next Generation Season 1, Deep Space Nine, Voyager, Picard Season 3, and Strange New Worlds Season 1.

It’s Spooktober – the spookiest month of the year! So I thought we could have a bit of fun and talk about some of the scariest aliens and villains that the Star Trek franchise has brought to screen.

Star Trek isn’t a franchise that’s well-known for being all that frightening. I don’t think that’s a controversial statement at all – in fact, I’d wager that most TV viewers would consider it pretty tame, especially when thinking about the horror genre and alien monsters! But that doesn’t mean Star Trek is never scary. There are some wonderfully atmospheric episodes and stories scattered throughout the franchise’s fifty-eight-year history that have some of those more frightening elements.

Still frame from Star Trek: Picard Season 3 (2023) showing a Borg cube.

Today, rather than talking about individual stories or episodes, what I’d like to do is pick out some of the franchise’s scariest aliens, monsters, and villains – and talk about why they work so well, why they’re so intimidating, and perhaps even just the potential they have to be frightening or scary in future stories.

My usual caveat applies: everything we’re going to talk about is the entirely subjective opinion of one person only. If I miss something you think is blindingly obvious or if I include a “scary” alien that you think isn’t frightening in the least… that’s okay! There’s plenty of room in the Star Trek fan community for disagreement and differences of opinion.

With that out of the way, let’s talk about some of Star Trek’s scariest aliens and villains!

Number 1:
Q and the Q Continuum

Still frame from Star Trek: Picard Season 2 (2022) showing Q.

The Q are on the list less for their out-and-out fear factor and more for their potential. I don’t think there have been many terrifying or bone-chilling Q appearances – though I will entertain the argument that Q’s penchant for randomness can have an unsettling or unnerving quality. Things like conjuring up aliens in Napoleonic uniforms or a post-atomic courtroom would be incredibly frightening in real life, even if they’re portrayed more as chaotic and wacky when we see them unfold on screen.

The Q Continuum’s real fear factor comes from their apparently unlimited power. No other alien race in Star Trek is as powerful as the Q, and they could quite literally wipe out humanity, the Federation, or even the entire galaxy with a wave of the hand. Although we always see Q as humanoid, their true form is a mystery, and their power seems to be without limit – and without a reliance on technology. No war against the Q seems possible, and if they ever chose to move against the Federation (which they could do for reasons beyond our comprehension, or to prevent some kind of conflict in the far future that we have no inkling of right now) they could be far more destructive than even the Borg.

Number 2:
The Gorn
(As they appear in Strange New Worlds)

Still frame from Star Trek: Strange New Worlds Season 1 (2022) showing a juvenile Gorn.

The Gorn are one of Star Trek’s oldest alien races, appearing in the first season of The Original Series. But after that initial appearance and a few scattered mentions through The Next Generation era, they didn’t show up on screen again until Enterprise. That depiction wasn’t great, in my view – it relied too heavily on CGI that didn’t look great at the time and hasn’t aged well. But the return of the Gorn in Strange New Worlds has been a triumph.

After several episodes built up the terror of Gorn raids on the Federation, it was the episode All Those Who Wander that really showed us what this new depiction of the Gorn can do. Strange New Worlds’ writers unleashed the Gorn in an episode that, more than any other in the franchise, leans into the horror genre. The Gorn are depicted almost like the Xenomorphs from the Alien film series, possessing strength and stealth abilities that left the away team cornered.

Number 3:
The Founders/Changelings

Still frame from Star Trek: Deep Space Nine showing a changeling in their gelatinous state.

Maybe this one is a little controversial, but after the way Changelings were depicted in Picard’s third season I think we have a pretty good case to include them as a frightening bunch! The idea that shape-shifters could infiltrate Starfleet and the Federation was addressed in a fantastic Deep Space Nine two-parter: Homefront and Paradise Lost. These episodes took more of a political thriller/drama approach to the topic, but the core idea is a deeply unsettling one.

With the Dominion playing a growing role in Deep Space Nine, the idea of Changeling infiltrators was scaled back and only used sparingly – probably because it’s not an easy story to write or pull off successfully. But Picard Season 3 brought the idea back in a creative way, showing how deadly Changelings could be and how a Changeling plot could be an existential threat to the Federation.

Number 4:
The M-113 Creature
(a.k.a. The Salt Vampire)

Still frame from Star Trek: The Original Series Season 1 (1966) showing the M-113 Creature.

The first ever alien to appear on The Original Series remains one of the franchise’s most frightening! The episode The Man Trap kick-started the Star Trek franchise back in 1966, and the Salt Vampire was the first alien that audiences saw Kirk and the crew wrangling with. As discussed above with the Changelings, the alien’s ability to change shape and blend in added to its fear factor – but moreover, its true appearance is pretty unsettling even today. There’s something to be said for those old rubber suits, eh?

The Salt Vampire is a sci-fi take on ancient legends and creatures from folklore, and that gives it a uniquely frightening feel. Preying on some of these old primordial fears lends the creature a genuinely intimidating vibe, and its grotesque appearance just adds to that. The Salt Vampire is, however, a tragic figure, as it appears to be the last of its kind; more akin to an animal acting out of instinct than a truly nefarious villain.

Number 5:
The Borg

Still frame from Star Trek: First Contact (1996) showing a Borg drone.

In my essay The Borg: Space Zombies, I go into a lot more detail on this topic, but the condensed version is this: the Borg fill a similar role to zombies in horror fiction, while also picking up on both Cold War-era fears of brainwashing and concerns about technology getting out of control. The idea of assimilation is incredibly clever, as it turns every ally the heroes lose into a new enemy to fight, making the Borg grow in strength at the exact same rate as Starfleet weakens.

The idea of being assimilated and losing one’s mind and identity is arguably a fate worse than death – and we’ve got several examples in Star Trek of ex-Borg wrangling with the consequences of what the Collective forced them to do. I would note that the Borg’s fear factor has declined over the years, particularly during the latter part of Voyager’s run. Seeing Starfleet triumph over the same adversary again and again – no matter how intimidating it may be on paper – does start to take the shine off things.

Number 6:
Armus

Still frame from Star Trek: The Next Generation Season 1 showing Armus.

Armus has the distinction of being the first alien monster to kill a main character on a Star Trek TV series. There were many ways The Next Generation’s writers could have written out Tasha Yar when Denise Crosby opted to quit the show, but killing her off was a bold move. And doing so in such a brutal way, with Armus not even batting an eye at her death… it was quite something to see.

If you have the DVD or Blu-ray of The Next Generation it’s worth watching the actors and producers talk about working on the episode Skin of Evil, because creating Armus and performing around the inky-black oil slick was incredibly difficult for everyone involved to say the least! Jonathan Frakes in particular had a very tough time with Riker’s scene when he was pulled under the surface. Armus is a scary-looking villain, and also one that had a profound, long-lasting impact on The Next Generation.

Number 7:
The “Whale Probe”

Still frame from Star Trek IV: The Voyage Home (1986) showing the Whale Probe.

Although the tone of The Voyage Home is pretty light-hearted and comedic, the so-called “whale probe” that kicks off the plot is an incredibly terrifying adversary, when you think about it. The probe disables Starfleet vessels with incredible ease, and is resistant to weapons and all attempts at communication. The people of Earth have no idea what it wants, what its purpose is, or how to reason with it.

This monolith simply arrives unannounced, doesn’t declare its intentions, and seems to wreak havoc on Earth and Starfleet. That’s a pretty scary concept, in my view, as it could’ve gone pretty badly for everyone involved if Kirk and the crew hadn’t intervened!

Number 8:
The Pah-Wraiths

Still frame from Star Trek: Deep Space Nine Season 6 showing Jake Sisko possessed by a Pah-Wraith.

As with Armus, there’s something distinctly “evil” about the non-corporeal Pah-Wraiths. The way they’re presented in multiple Deep Space Nine episodes, where they’re deeply entwined with Bajoran religion, makes them out to be akin to demons or dark spirits – and we even see them “possess” several different characters. Their banishment to Bajor’s fire caves also ties into this demonic analogy.

In later seasons, Gul Dukat gets involved with the Pah-Wraiths, leading a cult on Empok Nor that’s genuinely unsettling in its depiction. The Pah-Wraiths have magical books, the power to turn people blind, and the desire to conquer the Prophets’ domain in the Wormhole; a truly frightening group!

Number 9:
The Conspiracy Parasite-Aliens

Still frame from Star Trek: The Next Generation Season 1 showing a parasite-alien.

The end of The Next Generation’s first season introduced a race of parasitic aliens that infiltrated Starfleet. Allegedly, the parasite-aliens were supposed to be connected to the Borg in some way, but this angle was later dropped. Still, they’re more than frightening enough on their own terms, and the idea that Picard and the crew wouldn’t be able to tell who was infected and who to trust made for an entertaining story.

Here in the UK, one scene toward the end of Conspiracy was cut from the original broadcast because of how gruesome it was! You know the one: where the “mother” parasite is killed and violently explodes. There’s something just unsettling about earwig-like alien parasites… just like the Ceti Alpha eel from The Wrath of Khan. Star Trek hasn’t revisited the parasite idea for a long time – maybe it could make for a fun and horrifying future episode?

Number 10:
The Krenim

Still frame from Star Trek: Voyager Season 4 showing Annorax.

The Krenim appeared in the Voyager two-parter Year of Hell, using their time-manipulation technology as a weapon. Repeated Krenim attacks against the USS Voyager left the ship in ruins, running on fumes, and many members of the crew dead or maimed. The captain of the Krenim time-ship, Annorax, was Khan-like in his single-minded obsession with restoring the Krenim colony that housed his wife and family, making him a frightening adversary.

Year of Hell is a pretty shocking episode, particularly in its second half. Seeing Voyager badly damaged, with whole parts of the ship uninhabitable, really hammers home how dangerous the Krenim and Annorax are as villains, and for a time their technology really does seem to be more than a match for Janeway and the crew.

So that’s it!

Still frame from Star Trek: The Original Series (1966) showing a Gorn.

We’ve picked out what I consider to be a selection of Star Trek’s most frightening aliens, monsters, and villains to celebrate the spooky season.

There are plenty of others that we could’ve included – either for their fully-blown fear factor or for their potential to do serious harm to our Starfleet heroes. And there are quite a few Star Trek episodes – a surprising number, really – that either lean fully into the horror genre or that have jump-scares or other frightening or unsettling moments. Last year, I put together a list of a few of them, which you can check out by clicking or tapping here if you’re interested!

So I hope this has been a bit of fun! I hope you’re having a fun and spooky October – and stay tuned, because I have a couple of other Halloween-themed ideas that may (or may not, time depending) make their way onto the website before the 31st. Don’t have nightmares!


Most of the films and episodes discussed above are available to stream on Paramount+ in countries and territories where the platform is available. They’re also available for purchase on DVD, Blu-ray, and video-on-demand. The Star Trek franchise – including all films, episodes, and other properties discussed above – is the copyright of Paramount Global. This article contains the thoughts and opinions of one person only and is not intended to cause any offence.

Aliens of Star Trek: The M-113 Creature

Happy Star Trek Day! Today marks fifty-four years since the first episode of The Original Series aired on American television, kicking off a franchise which is still going strong today. The Man Trap featured an alien called the M-113 Creature, but you may know it by its unofficial name: the Salt Vampire!

The early production history of Star Trek is complicated! After The Cage – the show’s original pilot – wasn’t picked up by network NBC, a second pilot was commissioned. This was very unusual, and rumours abound as to what happened. Gene Roddenberry and co. went away to work on a new pilot, and what resulted was Where No Man Has Gone Before. The new pilot dropped most of The Cage’s characters – only Spock would be retained – and reworked the series. It ultimately led to Star Trek being greenlit, and the show was picked up for a full season. Several episodes were filmed, including The Man Trap, and when NBC came to deciding the order in which the stories would air, it was selected as the premiere as its story was considered easier to follow by the executives at the network.

Happy 54th anniversary to The Man Trap… and to Star Trek!

So that’s a potted history of how The Man Trap came to be Star Trek’s first episode, despite the fact it wasn’t filmed first! The episode would see the crew take on a nefarious alien which was the last of its kind: the M-113 Creature.

I’m going to go out on a limb and say that I really like the design of the creature and the special effects used to pull it off. The heavy rubber suits used for some of The Original Series’ aliens and creatures have a distinct aesthetic, but it’s one I think really works. The suits were very cleverly and lovingly designed, and compared to a lot of contemporary special effects have held up remarkably well over the decades. I’d even compare these kind of practical effects very favourably to lots of digital effects and CGI; no one will ever convince me that Enterprise’s CGI Gorn looks better than The Original Series’ rubber suit!

I think this Gorn still looks pretty good in 2020!

Though the M-113 creature was only seen in its true form very briefly, the same kind of special effects brought it to life in a horrifying way, yet with a unique look that is now emblematic of the Star Trek franchise. Many people who are only dimly aware of Star Trek would recognise the M-113 Creature and be able to identify it as a Star Trek alien; in that sense the creature is up there with races like the Borg and Klingons as being iconic.

It’s been great to see a couple of recent references within Star Trek to the M-113 creature. It appeared in Ephraim and Dot – an animated episode of Short Treks that aired back in December. And just last week we caught a glimpse of the M-113 Creature in Cupid’s Errant Arrow, the fifth episode of Star Trek: Lower Decks. These fun little “Easter eggs” to Trekkies were greatly appreciated, and serve as a reminder of Star Trek’s origins all these years later.

The M-113 Creature seen in Ephraim and Dot…
…and again in Cupid’s Errant Arrow.

Though the creature the crew of the Enterprise encountered in The Man Trap was said to be the last of its kind, it’s arguable that may no longer be the case. Being mentioned in Lower Decks could be seen to imply that further M-113 Creatures have been discovered later in the 23rd and 24th Centuries, so we may not have seen the last of this iconic villain.

Nicknamed the “Salt Vampire” because of its ability to extract all of the salt from its victims, the M-113 Creature was a shapeshifter, able to take the form of other species, including humans. It also seems to have been sentient – able to mimic human behaviour and even hold in-depth conversations and form relationships.

The M-113 Creature was able to assume many forms.

Though distinct from later shapeshifting races – most notably the Founders of the Dominion – the M-113 Creature was the first such alien encountered in Star Trek. We’ve since seen a number of others, all of which owe at least a little something to their predecessor from The Man Trap. The concept of a shapeshifter is frightening, and that aspect has been used to great effect in several Star Trek stories.

The M-113 Creature also possessed several other abilities that made it a formidable adversary: it could telepathically sense the minds of sentient life forms – including humans – and use what it found to choose its appearance. This kind of tactic allowed it to get close to its prey and get them to let their guard down. It was also capable of paralysing people in order to get close to them when in its true form, and was incredibly physically strong – far more so than humans and Vulcans.

The M-113 Creature in its true form.

In The Man Trap, the sole surviving M-113 Creature (that we know of) took the form of Nancy Crater, a woman Dr McCoy had known; “that one woman”, as Captain Kirk put it. It lived with Crater’s husband, Robert, on the planet M-113 for a number of years. It was speculated that there had once been a civilisation of M-113 Creatures, but that the majority had gone extinct when the planet’s supply of salt was used up. Robert and Nancy Crater led an archaeological expedition to the world, encountering what could be the last survivor of the race.

Despite possessing some degree of sentience, it wasn’t possible for the crew of the Enterprise to reason with the M-113 Creature that they encountered, and it was killed by Dr McCoy while attempting to feed on Captain Kirk. If it were possible to negotiate with it – or others of its race – Starfleet could have provided the aliens with a supply of salt in exchange for peace. Perhaps such a story could be included in a future episode of Star Trek!

The M-113 Creature after being killed by Dr McCoy.

Despite its monstrous appearance and villainous role in the story, the death of the M-113 Creature in The Man Trap is a sad occasion. Potentially the last of its kind, the entire race and everything they had created now seems lost to history. Starfleet aims not only to seek out new life, but also to find ways – where possible – to peacefully coexist. It’s ironic, considering subsequent Star Trek stories, that the first encounter with an alien ended with its death!

But in a way, the aftermath of the M-113 Creature’s death is what established Star Trek as being more than just typical mid-century B-movie sci-fi fare. It took an emotional toll on Dr McCoy to kill what he thought was his long-lost love, and it took a toll on Kirk and the crew to have killed off the last member of a species. But as the Enterprise prepares to leave orbit, Kirk, Spock, and McCoy gather on the bridge and remember the creature in what was a very poignant moment.

The crew of the Enterprise at the end of The Man Trap.

It’s moments like this, across The Original Series’ early episodes, that set up Star Trek as being something special. There was more to the story of the M-113 Creature than just a horrible monster for our heroes to outsmart. That story was emotional and complex, bringing up issues of morality that other television series and films struggle to get across even today.

Star Trek offered – and continues to offer, fifty-four years later – much more to its audience than just exciting space adventures. This is why the franchise has endured so long, and it all began on the 8th of September 1966 with The Man Trap and the M-113 Creature.

Star Trek: The Original Series is available to stream now on CBS All Access in the United States and on Netflix in the United Kingdom and other countries and territories. The series is also available on DVD and Blu-ray. The Star Trek franchise – including The Original Series and all other properties listed above – is the copyright of ViacomCBS. This article contains the thoughts and opinions of one person only and is not intended to cause any offence.