(covers information from several alternate timelines)
In 2252, a transport ship crashed on Thasus, with a young boy, Charlie Evans, the only survivor. In order to keep the boy alive, the Thasians cared for him and granted him their psychokinetic abilities. In 2266, Charlie escaped from Thasus on the Antares.
He was later transferred to the USS Enterprise, which was to transport him to Colony Alpha 5, where he would be reunited with his closest living relatives. Charlie's powers proved dangerous, however, as he used them for his own benefit without regard for the consequences to others. Realizing that Charlie was gone, the Thasians retrieved him from the Enterprise, and took him back to Thasus, where he would no longer pose a danger. (TOS: "Charlie X")