The fun-loving mutant behomoth known as Strong Guy has had a very tortured life despite his constant good nature. Before his mutant powers manifested, Guido was the class clown. He played all the practical jokes and made fun of the teacher because he was also the best student and all the other kids despised him for it. Added to that, he wasn't exactly a lady's man. He was a clutz and small and skinny and wore glasses, which just made all the other kids pick on him more. When he finally got up the courage to approach the girl of his dreams, her boyfriend began beating him up. Somewhere during the fight, Guido got tossed into the road. It was then that a school bus hit him, causing the first manifestation of his power. Absorbing the kinetic energy of the impact, his arm swelled up to huge proportions, while he flailed around in the street. Over the next few days, various other collisions caused him to grow to his current size. At that age, he did not yet know that he had to release the strength or else remain that size forever.

   Somewhere along the way, Guido became the body gaurd of rockstar Lila Cheney. Together the pair traveled throughout the universe where she was a superstar. When Lila came back to earth, he accompanied her. He became involved with the X-Men when Dazzler washed up on Lila's beach house shore. He helped her to regain her memory after traveling through the Seige Perilous, and came into contact with other X-Men through her. Making his way to Muir Island, he became entrapped in the Shadow King's influence.

   Upon breaking free, he joined the new X-Factor to try and make the world better accept mutants. It was his outburst that first coined the term 'geecee" aka Genetically Challenged. Though he and Havok clashed over a number of issues, Guido was beginning to fall in love with Polaris. Nothing ever came of the crush but heartbreak and eventually in battle, Guido collapsed under too much strain to his heart (though not from love). Forge designed a device to keep him alive, but it wasn't for some considerable time that he came out of his coma state. When he finally did, he left with Lila again and is currently traveling the stars on her most recent galactic tour.