Born with a unique disorder, lacking connections between his brain and his nerves controlling his five senses; hearing, smell, sight, taste, and touch. Barry spent his entire life hospitalized, without outside stimulation, causing Bauman's mind to turn inward, discovering an amazing sense of self; hungry for more knowledge, and theorizing that there might exist a realm outside of himself, Bauman fully explored his own mind, learning to access all of it, rather than just the 10% man normally used. Reaching out with his new-found mental capacity, he discovered the existence of others, but was disturbed to find that he was different from them. Learning to take control of his nurse, Tom Vocson, Bauman finally experienced the five senses through him, and he used Tom to read through endless text, learning all he could of mankind's knowledge. Bauman's powers to affect the outside continued to grow,developing both telekinesis and the ability to affect others emotions; as his telekinesis grew, he amused his self by causing disasters. Desiring revenge on humanity for spending billions on weapons but nothing to cure his condition, Bauman reached out into the stars; at first he planned to crash an asteroid into the planet, but deciding that would be too quick,he instead decided to blank out the stars, along with the light they produced, systematically one by one, so that mankind could watch fearfully as the skies slowly darken, until finally he extinguished the sun itself.
Far out in the Andromeda galaxy, Adam Warlock was perplexed by numerous stars' sudden disappearance. Using his Soul Gem, he tracked the problems origin to Earth; however Bauman sensed his intent, and confronted him with a mental projection. Bauman adopted Warlock's description of the Star Thief as his name, Bauman challenge Warlock seeing him as an amusing diversion; Star Thief plagued him with rock golems, winged demons and space sharks. Exhausted by the last, Warlock caught Star Thief's mental projection off-guard and stole a piece of Bauman's soul to revitalize himself. Angered, the Star Thief created a fiery host body, but Warlock destroyed it, and quickly made his escape through a black hole, out of Star Thief's reach. Anticipating Warlock would reappear near Earth, Star Thief gathered his powers, unwittingly releasing his hold on Tom Vocson. While Star Thief was distracted taunting Warlock, who had just discovered that he had grown too large to enter Earth's solar system, Vocson, now aware of Star Thief's villainy, seized the opportunity and shot Bauman's body dead. Sometime later, when Warlock was absorbed into the Soul Gem, he learned that a portion of the Star Thief's soul had also survived alongside the souls of the gems other inhabitants.
