When Felix was born, he looked exactly as he does now, with the only exception being that he was baby-sized.
Doctors were stumped. There didn't seem to be anything wrong with him. He behaved like a baby would, ate how a baby would. The only strange things about him were his appearance and the apparent "strange feeling" his mother would get when he looked at her for too long.
Felix was six years old when he first learned of his abilities. He had seen kids in his kindergarten class flip their eyelids to scare other kids. When he thought about doing it himself, his eyelids flipped automatically. Throughout the day, he found more strange things that he could do with his body that no one else could, and used those things to scare his classmates. His father picked him up early, because at hearing the news, his mother was too afraid to see him at the time.
From then on, Felix became more and more mischievious. There was no logical reason for it. His parents always tried to ingrain in Felix's brain to be kind to others, and their behaviour reinforced their mindsets. His mother became convinced that he was some kind of spawn of the devil, but then what would that make her? This mindset sent her down a negative spiral, leaving Felix's father to be the primary one to take care of him. Of course, this stressed him out, as well.
Felix didn't care at all for his parents' troubles. He kept doing what he wanted to do, and it was difficult for his parents to discipline him, because he didn't seem to care about anything. One day, when he was twelve, he decided to just leave. He left no clues as to where he was going, because even he didn't know. He decided that his parents were too annoying, anyway. He was just going to do what he wanted from then. He began stealing to survive, and spent years messing with people, exploring places, and doing whatever the hell else he wanted to. Life was good.