Tommy Starnes was son of Professor Starnes, leader of the Starnes Exploration Party on Triacus in 2268. Tommy was the oldest of the surviving children from the Exploration Party and their quasi-leader. He, like the other children, showed no grief over his parents' deaths.
Tommy induced hallucination and mental incapacitation in the crew to hijack the ship. Once the children were shown tapes of their parents and their graves, demonstrating to them that Gorgan was an evil force, they refused to obey him and the Gorgan was rendered impotent. Tommy and the rest of the children returned to normal. (TOS: "And the Children Shall Lead")