The Star Trek franchise has entered into a Golden Age in the 2020s. The science fiction juggernaut, initially launched in 1966, now has multiple series running simultaneously. There have been eight live-action and three animated TV series to bear the name Star Trek, four of which are currently on air. While Star Trek is science fiction, it allows for comedy, horror, suspense, and even musicals.
With nearly sixty years worth of television and among the myriad of episodes, there have been some spine chillers. Episodes that emphasize bloodthirsty aliens and mind-bending murder are often fan favorites. So now, we present the ten scariest episodes of Star Trek.
Related: 10 Examples of Ingenuity Inspired by Star Trek
10 “The Man Trap,” The Original Series Season 1 Episode 1
In the very first episode featuring Captain Kirk, the crew of the USS Enterprise comes face to face with a soul-sucking shapeshifter. When Kirk, McCoy, and Darnell beam down to a planet for a routine away mission, they meet McCoy’s ex-girlfriend, who appears to each of them as a different woman—although none of the men know it. We discover that this is not Dr. McCoy’s old flame but an alien being that can take the shape of anyone it comes in contact with. It feeds off the salt within those people, leaving red marks on their faces, and then assumes their lives until it finds its next victim.
As McCoy’s ex, she boards the Enterprise and wreaks havoc. A string of corpses lacking any trace of salt in their bodies begin to litter Sick Bay. In the end, McCoy is forced to kill the creature as it turns from his former lover into a hideous monster and back again. While the 1960s lack the CGI monsters of today’s Trek productions, “The Man Trap” uses lighting, directing, intense music, and talented acting to create a horrific space adventure in the first ever aired Star Trek episode.[1]
9 “Whispers,” Deep Space Nine Season 2 Episode 14
This season two DS9 episode focuses on and is narrated by Chief O’Brien. After returning from an away mission in the Parada System, O’Brien finds that everyone around him behaves strangely, even his wife and daughter. A string of strange encounters drives the chief of operations to investigate. He becomes convinced that imposters of some sort have taken over the station. Specifically, he believes that Keiko is not “his Keiko.” He heads back to the Parada System. He’s now theorized that the Paradans are directly connected to his current situation.
On the run, O’Brien’s fear and wild curiosity at what has thrown his world upside down builds and builds until he’s finally cornered with nowhere left to run. In the end, the chief comes face to face with his nemesis… himself. Unfortunately for our narrator, he is just a clone created by the Paradans. He is the imposter and a sleeper agent designed to assassinate a high-ranking dignitary. He only realizes this after he has been fatally wounded. As the reality washes over him and the real O’Brien watches on in disbelief, the clone’s last thoughts are of Keiko.[2]
8 “Frame of Mind,” The Next Generation Season 6 Episode 21
In this mind-bending psychological thriller, Commander Riker uncontrollably switches between realities. Riker is performing in a play called “Frame of Mind,” in which his character is in a mental hospital accused of a vicious murder. At the same time, preparing for the role, he is simultaneously prepping for an undercover away mission. The play goes on the night before the mission, where Riker does a magnificent job and receives a standing ovation. But the applause suddenly stops, and he is in a mental hospital, just like the character in the play.
The commander proceeds to flip back and forth between the mental hospital and the Enterprise. He begins to lose his sanity and questions whether or not he is indeed Commander William T. Riker of the Enterprise. We find that he is being held in an alien psych ward where they are probing his mind for information. There, they use his recent memories of the play to create a warped reality.
Riker resists the alien technology, and his reality unravels before his eyes. Eventually, he wakes from the technology-induced nightmare in the foreign laboratory and frees himself. This episode keeps you guessing until the bitter end, leaving Riker and the audience with nightmares for weeks.[3]
7 “Dead Stop,” Enterprise Season 2 Episode 4
In this season two episode of the prequel series Enterprise, the lone Starfleet ship exploring the galaxy has been badly damaged in an encounter with a Romulan minefield in the previous episode. Desperate for repair help, the crew’s prayers are miraculously answered through an automated repair station. The sentient station floating in deep space adapts to fit the NX class ship, analyzes it, and prepares a maintenance program with multiple billing options. While it seems too good to be true, Captain Archer has little other choice, and the repairs begin.
Slowly, the tension rises as the AI’s sinister motives reach the surface. The station is reminiscent of 2001: A Space Odyssey. Director and Star Trek alumnus Roxanne Dawson voices the station with emotionless malice. Instead of paying with plasma, it turns out they’d be paying with crew members.
The station’s sinister plot is revealed when Ensign Mayweather is seemingly killed, but his body is switched with a replicant while he is transported to the station. Archer and T’Pol rescue him from a lab where he and other aliens are comatose and hooked to unknown machines. They escape and blow up the station, but as they depart, we see it repairing itself.[4]
6 “All Those Who Wander,” Strange New Worlds Season 1 Episode 9
Modern Trek has used new technology to bring back an old foe from The Original Series, the Gorn. Captain Kirk’s famous battle against the Gorn depicted a bipedal humanoid with lizard-like features. Captain Pike’s crew, however, engages in conflict with a much more vicious Gorn. CGI-created raptor-like aliens stalk the team in this Alien vs. Predator-type episode.
When a shuttle crew crash lands on a cold and technology-dampening planet, they find themselves in the middle of a Gorn breeding ground. Gorn are hatched from the bodies of their victims and immediately begin fighting for dominance. Other humanoid races are food to them; they are relentless killing machines. Throughout the episode, the crew faces their own demons and the monstrous Gorn. Although the team survives long enough to escape to the Enterprise, the encounter leaves them scarred emotionally and physically.[5]
5 “One,” Voyager Season 4 Episode 25
Absolute solitude would be a nightmarish prospect for anyone, but being an ex-borg, once connected to countless other minds, would make it unbearable. Nonetheless, that is the exact situation Seven of Nine finds herself in. Now four years into a seventy-year voyage back to the Alpha Quadrant, Voyager faces a vast region of space enveloped in a poisonous nebula.
The nebula’s toxic effects cause massive burns and disfiguration in several crew members. The crew is put into stasis to negate the nebula’s effects—all but Seven, whose Borg-enhanced body is immune, and the holographic Doctor, also immune. Before long, The Doctor’s systems are also affected by the nebula and offline. Seven now has roughly a month to operate the ship alone, facing hallucinations, paranoia, and the vast solitude of the nebula.[6]
4 “Context Is for Kings,” Discovery Season 1 Episode 3
As the new era of Trek began in 2017, we find Starfleet’s first mutineer, Michael Burnham, on her way to prison for betraying her captain and starting a war between the Federation and the Klingon Empire. Her transport ship is nearly destroyed but rescued by the USS Discovery. The mysterious Captain Lorca quickly puts her to work despite her status as a convict. In this episode, Discovery’s sister ship, the USS Glenn, has had an accident with their spore drive.
Burnham and an away team visit the sister ship to assess the situation. The Glenn’s crew are all dead. The ship’s interior is dark, with broken panels and bodies (Klingon and human) littering the corridors. The away team encounters a Klingon near a malfunctioning door. He steps out of the shadows, but the darkness flashes on and off, and he puts a finger to his lips to signal quiet. Then, with a deafening screech, he is enveloped and devoured by a monster. The away team runs for their lives.
We find later the beast is a Tardigrade, a space-fearing species of incredible strength and ability. Burnham is forced to escape the creature by crawling through Jeffrie’s tubes and then dropping into a shuttle before it tears into her flesh.[7]
3 “Genesis,” The Next Generation Season 7 Episode 19
In this terrifying episode, the crew of the USS Enterprise-D is exposed to a sort of virus that revives dormant ancient genes. They begin to exhibit strange behaviors and abilities, from beastlike mentality to prey-like fear and everything in between. All this happens while Picard and Data are on a shuttle mission to retrieve a rouge torpedo.
When they return, they discover the scene and must figure out a cure without being mauled, eaten, or poisoned by the crew. This episode is “A well-executed change of atmosphere, well-directed build-up, and just a unique, Twilight Zone-esque journey.” Picard is infected and begins to de-evolve into a lemur, but Data is unaffected and can save the day at the last moment.[8]
2 “The Thaw,” Voyager Season 2 Episode 23
Can you imagine something more terrifying than Michael McKean playing an evil electronic clown? Captain Janeway and company come across a planet that has suffered a natural disaster. They find five stasis chambers with humanoids in each one. Two have died from heart attacks, but three are still alive.
“Because all the pods are connected to a central computer, two Voyager officers volunteer to momentarily replace the deceased so that the other three can be revived without suffering brain damage. In doing so, the officers are trapped in a creepy circus phantasmagoria led by a sadistic and telepathic clown.” The psychotic clown, played by the incomparable Michael McKean, is the centerpiece of one of the scariest Star Trek episodes ever.[9]
1 “I Have No Bones Yet I Must Flee,” Lower Decks Season 4 Episode 2
Lower Decks is the animated half-hour comedy Star Trek spin-off based on an episode of TNG. In the most recent fourth season, the crew of the USS Cerritos encounters Star Trek’s most adorable and lethal character, Moopsy. Mariner and Ransom embark on what should be a routine mission to escort humans out of a menagerie, but the inevitable chaos ensues.
Mariner immediately shows her distaste for the zoolike establishment. While dressing down Narj for his business practices, they encounter the Moopsy, which Narj exclaims is his favorite. She continues her tirade as they reach the humans across from the Swamp Gobblers when they notice the Moopsy is loose. Narj loses his mind and screams in terror for everyone to run for their lives. To be clear, Moopsy is adorable and seemingly harmless.
Then Narj divulges that everything there is incredibly dangerous and that the Moopsy will drink their bones! As Mariner is asking how something can drink bones, the Moopsy leaps to the Swamp Gobbler’s shoulder with frightening quickness, opens up its maw, now showing large fangs, latches onto the Gobbler’s shoulder, and appears to suck out its entire skeletal system, before letting out an adorable “Moopsy” (apparently that’s all it can say). Narj dies before the encounter is over, and while the crew survives, the Moopsy is now known as the most horrifying creature in the galaxy.[10]