Spock is a major character in the original Star Trek series. He is the science officer and first officer on the star ship Enterprise, motivated to be logical, known for extremely repressed emotions, and high intelligence. This behavior results in him being a source of inspiration for Sheldon Cooper. He was played by Leonard Nimoy in the original series of Star Trek.
Appearance/References in TBBT
Spock appears as an action figure in "The Transporter Malfunction" (S05E20). The action figure is voiced by Leonard Nimoy and talks to Sheldon in his dreams.
In Sheldon's first dream, Spock reasons with and convinces Sheldon to play with the vintage mint-in-box 1975 Mego Star Trek Transporter, which is a gift from Penny. Sheldon rapidly wakes up from his dream, opens the box and plays with the toy. But he breaks the toy shortly after and switches it with Leonard's.
In Sheldon's next dream, Spock says he's very disappointed in Sheldon and bids Sheldon to do the right thing. When Sheldon refuses, he is attacked by a Gorn in the dream.
Sheldon later tries to switch back the toys, but cannot bring himself to do it. When Penny has persuaded Leonard to open his toy and Leonard finds out it is broken, Sheldon, after much difficulty, admits he has broken and switched his own toy with Leonard's. Then he hands over the switched toy back to Leonard.
In "The Codpiece Topology", the guys return to The Renaissance Fair with Sheldon portraying a Vulcan Star Fleet officer (probably Spock) from a landing party observing a planet that resembled middle-ages Earth which also included strange modernistic anomalies which Sheldon had noted on their first visit.
In "The Thespian Catalyst", Sheldon is taking acting lessons from Penny and they are performing a short skit based upon a story Sheldon wrote as a child. Penny portrayed Mr. Spock.
Spock is the Star Trek character that Sheldon most identifies with since he feels they are both intelligent, logical and unemotional. Also, when Sheldon describes their group as a Star Trek landing party, he is Spock, Leonard is Kirk, Howard is Scotty and Raj is the guy in the red shirt that is killed or is Lt. Uhura.
Leonard Nimoy, Spock's original voice, died from complications from COPD (chronic obstructive pulmonary disease) on February 27, 2015.
Sheldon & Leonard.
Spock in the second pilot.
Spock Clock