13 Terrifying Monsters Featured in the Star Trek Franchise

As a fan of the sci-fi/horror genre, I always enjoyed Star Trek for its terrifying alien creatures. In honor of today’s date, here are thirteen monsters—from both the original series and its follow-up offerings—that captured my imagination.

The Gorn Captain


Lacking a trace of emotion in his glittery eyes and possessing many times the strength of an average human, the Gorn captain—a hissing, reptilian humanoid voiced by Lurch actor Ted Cassidy—maintains a formidable presence in his one and only Star Trek appearance to date.

The Talosians


By employing mind control to reward, punish, and manipulate lesser evolved species, the Talosians—telepathic, giant-brained aliens from Talos IV—present an ominous threat to Captain Pike and the original Enterprise crew.

The Remans

Reman Viceroy

Modeled after Count Orlok from Nosferatu, the Remans offer a grotesque, primitive contrast to their shrewd and civilized Romulan counterparts.

Balok’s Puppet

Balok Puppet

Though not technically a monster (or a living creature at all for that matter), Balok’s puppet gives off a creepy, hollow stare while “communicating” through a viewscreen—an aspect that, when accentuated by the aforementioned voice of Cassidy, generates an air of suspense prior to Kirk’s implementation of the Corbomite Maneuver.

The Ceti Eels

Ceti Eel

Used by Khan Noonien Singh to extract information from Chekov and Terrell, the eels of Ceti Alpha V enter the ear canal of a humanoid host, wrap themselves around the cerebral cortex, and render the victim extremely susceptible to suggestion—a horrifying concept, especially when coupled with the intentions of a maniacal, genetically augmented sociopath.

The Horta


A silicon-based lifeform, the Horta employs a corrosive acid to tunnel through solid rock and disintegrate human flesh.

The Borg

Locutus of Borg

Essentially cybernetic zombies who assimilate free-minded organisms into a vast collective, the Borg earn their standing as the most frightening antagonists ever featured in the Star Trek franchise.

The Melkotian


When addressing the Enterprise crew, a Melkotian—a telepathic being similar to the Talosians, albeit more sadistic in nature—appears as a floating, disembodied head with green skin, two ominously bright eyes, and strips of flesh dangling from an elongated neck.

The Genesis Worms

Genesis Worms

Having evolved from the microbes on Spock’s torpedo coffin, the giant worms on the Genesis Planet resemble giant maggots, slither in a snake-like motion, and demonstrate powerful constrictive force—nearly enough to strangle a Klingon captain.



Devoid of a moral compass, Yarnek—another silicon-based lifeform—arranges a terrible conflict involving Kirk, Spock, Abraham Lincoln, and other historical figures in order to study human conceptions of good and evil.



Also known as Jack the Ripper, Redjac—a parasitic, non-corporeal entity that feeds on the pain and fear of its victims—moves from planet-to-planet and, with the help of a humanoid host, enjoys committing crimes of a heinous variety.



A black, oozing mass of hatred, malice, and nihilism, Armus—remembered for killing Tasha Yar in cold blood—deserves its reputation as the vilest creature in Star Trek history.

The Salt Vampire

Salt Vampire

The sole surviving member of a predatory, shapeshifting alien species, the M-113 entity (better known as the Salt Vampire) relies on suctioning force to drain sodium from human bodies—a ghastly, agonizing, and fatal (if uninterrupted) process.

What other Star Trek monsters are worth acknowledging? Post your own selections in the comment section below.