"Most seventeen year-olds do.""
Evans was born in 2249. Three years later, in 2252, he was the sole survivor of a transport ship crash on the desolate planet Thasus. The Thasians granted Evans his wide array of powers so that he could survive on their inhospitable world. Although they were able to restrain him temporarily, they were unable or unwilling to remove the powers.
Evans' powers included:
- The ability to make matter vanish, to create matter, and to rearrange the structure of matter
- The ability to influence the operation of mechanical devices
- The ability to alter the physiology of living beings and to influence their mental processes
Evans spent years there before the Antares discovered him in 2266, by which time he was 17 years old. During his time on the cargo ship, an Antares crewmember taught Evans card tricks. Using his psionic powers, he eventually took control of the Antares and its crewmembers. This ship transferred Evans to the USS Enterprise so that he might be reunited with his only known relatives on Colony 5.
Aboard the Enterprise, Evans claimed to have learned to speak by talking to the crashed ship's memory banks. He'd survived on food concentrates for a time, discovering edible native foods before his supplies were exhausted. Spock and McCoy debated this, Spock contending that Charlie's survival argued for the existence of some form of intelligent life on Thasus. There were gaps in Charlie's knowledge, and he demonstrated great immaturity on a number of occasions.
When Captain Ramart of the Antares attempted to warn the Enterprise about Evans, the boy removed the baffle plate on the shield of the Antares energy pile. This event resulted in the destruction of the Antares. While Spock believed that this act demonstrated that Evans had a total disregard for life, Kirk argued that he was a child who didn't understand what life was. Evans rationalized his act by saying. "It would've blown up anyway. Well they weren't nice to me! They wanted to get rid of me. They don't now."
As before on the Antares, Evans gained control of the Enterprise. Kirk speculated that he might be a Thasian, but McCoy's medical scans showed Evans' physiology matched that of 23rd century Humans, leading McCoy to believe that, despite his abilities, Evans was Human. His downfall came about because he had overextended himself and the crew took advantage of this to overwhelm him further by turning on all the technology aboard the starship.
The Thasians, having discovered Evans' departure from their world, caught up to him before the Enterprise reached Colony 5. Claiming it was impossible for Evans to live a normal life, they transported him aboard their vessel and departed.
Pressed to explain what became of the objects he made "go away", Evans could not or would not do so. Whatever happened to them, they were not destroyed, since the Thasians were able to restore them. It was probable that Evans didn't fully understand his powers. (TOS: "Charlie X")