Federation crews have always preferred to view exploration as a scientific and diplomatic effort. However, some threats were ultimately too horrifying to prompt any reaction except to fight, escape, and survive.

Star Trek’s horror villains, although undeniably terrifying for the affected ships, have come to occupy a beloved section of the canon by virtue of their pulp-heavy science fiction themes -- and the thrill that comes from watching our usually staid and rational Federation crews confront true terror.

Spanning from witches to germs, these are just a few of the scariest villains ever to haunt the galaxy. Again, these are just a few; many fans will cite their favorites, including the Borg Queen, the Zombie-Vulcans from Enterprise, the Salt Creature, Khan's Ceti eel that goes in Chekov's ear, and the creepy aliens in TNG's "Schisms."

Sylvia and Korob


Though based around a distinctly campy version of historical Earth ghost stories, Star Trek: The Original Series established the dramatic stakes immediately in “Catspaw,” as an entire away team returned with the dreaded phrase, “one to beam up.”

Materializing back aboard the Enterprise, the apparent sole surviving crewman immediately collapsed dead on the transport pad. Nonetheless, his lips delivered a message from the surface: The ship is cursed. Leave now, or die.

Captain Kirk, with Scotty and Sulu still unaccounted for on the surface, ignored the warning and assembled a second away team to investigate. It was immediately apparent that circumstances were not as they seemed, as the crew confronted a landscape shrouded in gothic fog and soon discovered an Earth-like castle, contradicting all of the Enterprise’s sensor readings.

Kirk’s team, after falling through a trap door, then met Korob and Sylvia, a be-robed wizard and his shape-shifting “witch” companion. Sylvia was able to manipulate the physical world with her mind, and had enslaved Scotty and Sulu as thoughtless automatons.

Sylvia, during an extended battle of wills, threatened to burn the Enterprise and locked it in an inexplicable force field to prevent rescue teams from launching. It was eventually revealed that Sylvia and Korob were aliens on an unexplained mission from “the Old Ones” that had gone awry once Sylvia experienced biological form and all of its tempting sensations.

Korob soon confessed he could no longer control Sylvia and feared her aspirations, prompting the crew to destroy his wand, seemingly the source of the aliens’ transmutation abilities. Stripped of their powers and reduced to small, feather-like forms, the aliens quickly perished, allowing the away team to escape with graphic memories of their real-life ghost story.

Macroscopic Viruses


Star Trek: Voyager’s “Macrocosm” took its cues straight from the language of cinematic horror, as the teaser found Captain Janeway and Neelix returning from a trade mission with the Tak Tak, only to discover that Voyager was adrift more than a light year from the scheduled rendezvous.

Once aboard, the pair were unsettled by signs that the crew had confronted a threat so terrifying they’d dropped tools in mid-task and vanished. The clues quickly became more ominous as deep buzzing could be heard in the ship, and the two came across holes punched through bulkheads, dripping with slime. After visiting an armory, a tentacle burst into the turbolift to attack Neelix, who fell ill and vanished with a scream soon afterward, leaving Janeway to make her way to the bridge and discover who — or what — had taken over the ship.

The true scope of events became clear when Janeway discovered crew members in the mess hall, including an infected Chakotay with a growth on his neck that released more of the buzzing attackers.

After being attacked by a mega-version of the creatures, Janeway met the Doctor in sickbay, who revealed that the ship had been taken over by a macrovirus — small organisms grown large and vicious.

Janeway served as a test subject for The Doctor’s antigen before the pair set out to deliver the cure throughout the ship, with the captain stalking the corridors, phaser rifle in hand. In full hero mode, Janeway soon lured the macrovirus creatures to the holodeck with infrared signatures, then administered the cure to her crew before tossing an antigen grenade into the holo simulation and ending the nightmare.

The Borg

"Q Who"

The Borg — all hail the Borg Queen — would eventually become a uniquely complex and multi-faceted antagonist, but Star Trek: The Next Generation first presented Picard and crew with a simple, single-minded threat in “Q Who,” the first-ever appearance of the Borg Collective.

It began, as many of Picard’s trials did, with a tantrum from Q, who swore he was ready to forego his omnipotent misbehavior in order to join the Enterprise crew as an advisor and guide to the galaxy’s dangers. Picard and Guinan declined his services, and Q responded by flinging the Enterprise into distant and uncharted space, saying he offered a “preview” of the threats they would soon face.

"Q Who"

As if on cue, a Borg cube appeared and transported a drone to the Enterprise’s engineering deck, where it began probing the ship’s systems. In an iconic sequence, Commander Worf was forced to use a full-power phaser blast to stop the drone, only to see it instantly replaced with a new member of the collective that had already adapted its shields to block Federation weaponry.

A scouting team, after temporarily disabling the cube, revealed the true nature of the threat they faced: A sea of mindless automatons, individual cyber-zombies controlled by a hive mind and unstoppable with mere weaponry.

Knowing they had no effective countermeasures, Picard was eventually forced to confess humanity’s helplessness before Q, who finally returned the crew to Federation territory, burdened by the knowledge of what terrors were heading toward Earth from the depths of space.

This article was originally published on September 28, 2018.

Stephen Ashley is a freelance writer currently taking a break from Brooklyn in the Catskill Mountains of upstate New York. He credits the syndicated TNG reruns of his youth for launching his love affair with Star Trek and all things science fiction.

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Star Trek: The Original Series
Star Trek: The Next Generation
Star Trek: Voyager