Space is scary, there's no doubt about it. We've only explored the tiniest fraction of our known galaxy and there's so much more out there we don't have the slightest clue about. Kind of terrifying, don't you think? Through all of its installments, Star Trek has delved into the potential horrors of what could await in space, and we've picked some of the spookiest for your reading pleasure.
The Devil in the Dark — Star Trek: The Original Series
Starting off strong, Star Trek would introduce horror into its universe during its very first season with the episode "The Devil in the Dark". Responding to a distress signal from a Federation mining colony, the Enterprise crew discover that the colony has been ravaged by a seemingly indestructible creature that has killed upwards of 50 workers and brought the mine's operations to a halt. Throughout the episode, the creature stalks the shadows, taking out more and more of the mining crew while Kirk and Spock try to stop it. The horror finally comes to a close when the two men find the creature, learning that it is a Horta, a species of alien that has been protecting its eggs from the miners, who have been unknowingly destroying them thinking they were useless silicon spheres. Kirk and Spock are able to broker a peace between the Horta and the colonists and return to the Enterprise.
Wolf in the Fold — Star Trek: The Original Series
It's scary enough to be accused of murder, but what's even scarier is to not remember commiting these crimes and potentially being executed for them. This is the predicament that befalls Montgomery Scott in the episode "Wolf in the Fold". When taking shore leave on Argelius II, Scott is discovered with a knife in hand, only steps away from a woman who had been murdered with that weapon. After Scott seemingly murders an Entrerprise officer who was sent to interview him, the crew holds a seance with a Argelian psychic that points to the presence of a malevolent entity known as Redjac possessing Scotty, after which point the psychic is murdered as well. Taking the investigation to the Enterprise, the crew then learns that the entity is none other than Jack the Ripper, who has somehow been possessing multiple hosts for years, feeding off the terror caused by his murders. With some quick thinking, the crew is able to trick the entity into repossessing its original host, after possessing the ship's computer and taking over, transporting both of them back into space with their atoms scrambled.
Schisms — Star Trek: The Next Generation
When the crew of the Enterprise-D all begin to have trouble sleeping and exhibit strange emotional outbursts, suspicions begin to build that all is not well aboard the ship. Using the holodeck to sort out what little memory they have of their experiences, the crew discovers that they all remember being brought to a dark room with what seems to be an operating table in it. With help of Dr. Crusher, the crew realizes that they are being abducted and experimented on by something that's coming through a rift located in the ship's cargo hold. Noting that he has been taken multiple times and that some of their crew is still missing, Riker volunteers to be taken back by their captors to stop them from messing with the crew once and for all. After being taken to the other side, Riker is able to save his missing comrades and return, while Geordi seals the rift just in time, keeping the creatures from ever returning.
Frame of Mind — Star Trek: The Next Generation
A mind-bending episode that calls into question not only the sanity of the cast members but also the audience, "Frame of Mind" keeps its audience guessing until the very end. When rehearsing a play of the same name, Commander Riker finds himself trapped in a cycle of switching between the Enterprise and an unknown alien mental asylum, where he is supposedly being held for killing a man in cold blood. When he's injected with sedatives, Riker finds himself back on the Enterprise, but soon realizes it's a hallucination and wakes up back in his cell in the asylum. Seeing hallucinations of his crewmates and oscilating back and forth between the Enterpise and the asylum by engaging in various destructive behaviors, Riker is finally able to wake up back in the real world and discover that he was captured by aliens and has an unknown device strapped to his head. Thinking quickly, Riker is able to escape and be transported back to the Enterprise, fully sure he's out of the mind-bending scheme.
Whispers — Star Trek: Deep Space 9
What if it turns out that you were actually not you at all? Yeah, we know that sounds crazy, but stick with us for a moment. Deep Space 9 chief of operations Miles O'Brien returns to the station after planning out details for peace talks between the Paradan government and rebels, when he discovers that the people on the station are starting to act strange towards him. His family will barely speak to him, his crewmates aren't including him in security discussions and tasks that would take him only a few minutes to do have been rigged to take up much more of his time. O'Brien begins to believe that there is a conspiracy happening aboard Deep Space 9. He flees, narrowly avoiding being taken by his crewmates. Returning to Parada, he discovers his crewmates speaking with the rebels, and inexplicably tries to attack them. After taking a fatal phaser wound, it is revealed that O'Brien was taken by the government and replaced with a replicant who was programmed to murder the rebels and end the peace talks. The same O'Brien who we followed the entire episode. See what we meant?
Empok Nor — Star Trek: Deep Space 9
Set on an abandoned Cardassian space station, "Empok Nor" is the closest Star Trek will get to the time-honored trope of a haunted house. Sent to the space station for a routine salvage mission, an away team consisting of O'Brien, Garak, Nog and four other officers end up having to fight off two ruthless Cardassian soldiers who were trapped in stasis pods, splitting the team up and leaving two officers dead in the crossfire. It's soon discovered that these Cardassians had been experimenting with a drug to increase their effectiveness in battle by increasing their xenophobic tendencies and that Garak, was accidentally exposed to the drug as well, turning him against the crew and causing him to accidentally kill one of the other officers. Taking Nog prisoner, Garak challenges O'Brien to a duel, with O'Brien only winning by rigging Garak's phaser to explode, knocking him out and ending the horror on the station.
The Thaw — Star Trek: Voyager
We have one word that sets the tone for the kind of horror present in this episode: clowns. Spooky right? Discovering a planet that had been subjected to an ecological disaster years prior, the crew of the Voyager find three aliens in stasis pods who have all had their brains tied to a central computer. Going into the virtual space inside the computer, Captain Janeway, Harry Kim and B'Elanna Torres all find that these aliens are being held hostage by a malicious clown, an entity created from a computer malfunction that lives off of the fear of the trapped hostages. In order to ensure the alien's freedom, Janeway offers to provide herself as a brain for the evil clown, so that it escapes the simulation, to which it accepts. This bargain was a trick though, as through their exploration of the simulation, they found that the clown was unable to affect holograms, trapping it in the simulation with a Janeway hologram as the computer was shut down for good.
Macrocosm — Star Trek: Voyager
When returning from an away mission with Neelix, Captain Janeway discovers that the crew has been infected by strange flying creatures that hatch from the necks of their hosts. While trying to make their way through the infected on the ship, Neelix is abducted by the creatures, leaving Janeway to fight for herself. She soon reaches sickbay and meets with The Doctor, who tells her that these creatures are part of a macrovirus that had been affecting a colony. The Doctor, who tried to help the colony while Janeway was off the ship, accidentally brought the infection aboard and infected the ship. Working as fast as they can, the remaining uninfected crew are able to create an antigen and send it through the air systems of the ship, eradicating the virus and saving the crew.