Trelane's species was a non-corporeal species that lived on another plane of existence. They apparently valued obedience and compassion, and regarded humanoid beings as the equivalents of pets. Their adolescents possessed extremely sophisticated technology capable of turning energy into matter by means of thought waves, and creating such complex objects as a planet and its natural atmosphere, and appear in Human form.
This species was first encountered by the USS Enterprise in 2267 when the ship was intercepted by the child-like Trelane. When the ship locked the transporter beam on to "all" living things, it did not establish a lock on Trelane, which meant that Trelane was "not a life form as we know it".
Following the encounter, Spock suggested describing Trelane under several classifications, including "pure mentality", "force of intellect", "embodied energy", or "superbeing". Kirk added "God of war", which Spock found to be unfitting, before settling on "a small boy, and a very naughty one at that." Spock felt that that "will make a strange entry in the library banks;" leading Kirk to conclude that he was "he was a very strange small boy." (TOS: "The Squire of Gothos")
According to the script, Trelane's parents were described as "two large pulsating globes of green light, one slightly larger than the other, both hanging in mid-air, radiating color."