What is This Thing Called Spock?
The planet Taragon had been colonised for over twenty years, and careful preparation had been made to exploit its valuable mineral resources. Perhaps not careful enough, though. Possibly a mine shaft had touched unexpected pockets of gas or a drilling rig had sunk too far. But the result was catastrophic…

Summary
Disaster strikes the mining colony on planet Taragon. A mining accident triggers a chain reaction resulting in volcanic eruptions and planet-wide upheaval. Emergency teams encounter an enormous organic mass emerging from the depths. Immediately after, the colonists riot in the streets, causing the governors to lock themselves in safe locations and send out a distress call.

The starship  receives the transmission, and Captain Kirk and Mr. Spock beam down to investigate. After being briefed on the situation, the two men go out into the wilderness and split up to search for answers. The ground beneath Spock erupts with tendrils and envelops him, despite his firing a phaser.

Some distance away, Kirk attempts to contact Spock, who is not responding to communicator hails. Kirk happens upon Spock in a clearing, who turns and quickly fires a phaser at his captain. Kirk manages to elude Spock and hides behind a plant, but sees Spock again in another area. Leaping out of hiding, Kirk punches Spock, knocking him unconscious, only to see three more Spocks arrive, all firing phasers. Running away from his pursuers, Kirk falls down a gully, seeing three more Spocks. Lying on the ground, he realizes that the Spocks cannot see him; they only react to sound.

Beaming back to the Enterprise, Kirk goes to the bridge, and Scotty reports that Spock is waiting for him in the micro-library. The real Spock explains that he was drawn into a brain-like mass that duplicated him. Reasoning quickly on events, he beamed back to the ship to study his data. The intelligence they encountered has normally lived beneath the surface of Taragon, and has the ability to absorb and reproduce matter to learn about it. Since Spock and the colonists reacted in a hostile manner, that is the way the duplicates behaved. The intelligence assumed that this was the way they normally acted.

Spock has Kirk accompany him back down to Taragon, and sits, while writing on a PADD, on a rock. Tendril-masses of cells coalesce around him. After some time, a visibly nervous Kirk sees the cells dissipate, leaving an unharmed Spock behind. The Vulcan reports success, reporting that he has established a telepathic bond with the intelligence. Since it absorbed him while he wrote, it learned his language. In its natural form, the underground is its native habitat, and it wants assurance that it will not be harmed further by mining.

Captain Kirk negotiates a peace between the intelligence and the colonists, with a plan to work together in the future. As the Enterprise departs, Kirk quips that they now have a place to go for spare parts, but Spock replies that they would be faulty, as he has seen enough faults in himself this mission.

Memorable quotes
"What do you make of it, Mr. Spock?"
"Mining explosions and natural disasters are not uncommon on uncharted planets. Nor is the appearance of alien life forms!"
 - Kirk and Spock, having a nonsensical conversation

"Only one thing in my favour… they all seem to be terrible shots!"
 - Kirk, dodging the phasers of three Spocks

"By learning our language from what I wrote, it can now communicate with us by telepathy!"
 - Spock, attempting to explain how he made contact

Background information 
 Since Scotty wears a gold uniform, this story must be set between  and .
 The planet Taragon may be named for the herb tarragon. Twenty years prior to the story places the start of colonization at circa 2245.
 Kirk wears a red uniform.
 Spock does research in a previously unseen area of the ship, the "micro-library". He examines what look like s, inserted into a workstation with a cluster of viewers.
 Spock initially rules out telepathy as an explanation for the colonists' behavior, but later guesses that the intelligence is telepathic.
 The lifeform appears to be one massive intelligence distributed across a mass of mimetic brain cells. Although there are references to several creatures, these only describe the replicants it produced. It is unclear if they were actually independent automatons or merely an extension of the distributed intelligence, as they did not speak and could not see.

Common motifs
There are a number of elements in this story echoed in other stories:
Improper mining techniques were later responsible for the destruction of the Klingon moon Praxis.
 The appearance of the mimetic lifeform resembles the alien seen in .
 The plot of this story is similar to the  comic story "To Walk the Night" in which Spock is also copied by a mimetic lifeform. Chronologically, that story took place earlier, so Spock's experiences there could have helped him deduce what was happening on Taragon. There are also similarities to the  fourth season episode , in which a mimetic lifeform copies the entire  crew.
 Miners also make disastrous first contact with a monster in .

Cover gallery

Characters

Regular Cast
 James T. Kirk
 Montgomery Scott
 Spock
 Uhura

Other Characters

Comics