1967 Star Trek Devil in the Dark

"The Devil in the Dark" is the twenty-fifth episode of the first season of Star Trek: The Original Series. It first aired on March 9, 1967, and is a highly regarded, thought-provoking episode that explores themes of tolerance, communication with the unknown, and empathy.
The USS Enterprise is summoned to the mining colony on Janus VI, where over 50 miners have been mysteriously and gruesomely killed by an unknown "monster" that can tunnel through solid rock. Captain Kirk, Mr. Spock, and Dr. McCoy beam down to investigate and help the paranoid miners stop the creature.
As they track the creature, which the miners call the Horta, they discover strange, seemingly useless silicon spheres. The crew initially believes they are dealing with a hostile, mindless beast, but Spock senses an intelligent presence and performs a mind-meld with the wounded Horta
The mind-meld reveals the astonishing truth: the "monster" is a mother Horta, a silicon-based life form, and the silicon nodules the miners were destroying were actually her eggs. She was killing the miners in a desperate attempt to protect her unborn children.
Rather than destroying the Horta, Kirk and Spock broker an agreement between the Horta and the miners. Dr. McCoy uses a silicon-based thermal concrete to heal the Horta's injury, and a peaceful resolution is reached, with the Horta guiding the miners to rich new mineral veins in exchange for the safety of her eggs.
Empathy and Tolerance: The central message of the episode is about overcoming fear of the unknown and demonstrating empathy towards vastly different life forms, a quintessential Star Trek ideal.
"I'm a Doctor, Not a...": This episode features the first instance of Dr. McCoy's famous catchphrase when he protests being ordered to treat a creature made of rock: "I'm a doctor, not a bricklayer".
Critical Acclaim: The episode is often cited as one of the best of the original series, with William Shatner reportedly considering it his favorite at the time of filming.
Behind the Scenes: The unique Horta costume was designed and worn by actor/stuntman Janos Prohaska, who inspired the story by crawling into the production office in an early version of the outfit.