Once, long ago, in ancient Greece, Biron was a centaur in love with the sorceress Circe. Biron saved Circe from an assassination attempt engineered by a rival wizard called Maldor, and as a reward he asked being turned into human. Circe gave him a transformation potion, unaware that Maldor had switched the vials, and Biron was irreversibly transformed into a white horse. In order to make up for what she believed to be her mistake, Circe brewed another potion which gave him "the might of Jove, the speed of Mercury, the wisdom of Athena, and the telepathic powers of Neptune", as well as immortality.
Enraged over his revenge being fouled again, Maldor used another spell to trap Biron on an asteroid in the constellation Sagittarius. Biron spent centuries trapped, until Supergirl's Kryptonian Rocket destroyed his asteroid by accident and freed Biron.
Biron trailed Supergirl's rocket back to the Earth, and found out his mysterious saviour was a super-hero. Having become obsessed with Supergirl, and hoping team up with her in the future, Biron let himself to be captured and taken to "Supergirl Dude Ranch", named after the Girl of Steel and located near from Midvale.
Aware of an impeding alien attack, Biron tried to warn Supergirl via telepathic dreams. Supergirl didn't understand her dreams featuring a super-horse -whom she named "Comet"-, but she found Comet thanks to them. Together, Supergirl and Comet managed to beat back an alien invasion. Unfortunately, Comet was sold to an animal trainer from Hollywood straight after.
Shortly after, an accident would cause Comet forget about Supergirl. Feeling restless, though, Comet escaped from captivity and wandered over a short while until he rescued a little girl from a fire. Comet was taken in by her parents and looked after until he was once again found by Supergirl, and his memory returned.
A while later, Comet would go to Planet Zerox and bust a scheme to overturn its ruler, a powerful wizard called Prince Endor. In gratitude, Prince Endor modified Circe's spell so Comet was able to turn into a non-powered human every time a comet passed through the solar system.
While human, Biron got a job in a rodeo under the name "Bronco" Bill Star. Meanwhile, Supergirl, unaware of Biron's new ability and identity and worried about his disappearance, was looking for Comet. Guided by her friend Lena's psychic powers, Supergirl dropped by Biron's workplace. Biron decided against revealing his identity, opting for romancing a clueless Supergirl, who believed him to be a normal man.
Thanks to Circe's potion, Comet is endowed with a good number of powers:
- Enhanced Intellect
- Metamorphosis: When a comet passes through the solar system he is in, he turns into a man. For a brief transition period, he is once again a centaur.
- Superhuman Speed
- Superhuman Strength
- Equestrianism: Thanks to his dual nature, Biron instinctively knows every movement a horse is going to make.
- This version of Comet, including all history and corresponding appearances, was erased from existence following the collapse of the original Multiverse in the 1985–86 Crisis on Infinite Earths limited series. Even though versions of the character may have since appeared, this information does not apply to those versions.
- 52 Appearances of Biron (Earth-One)
- 9 Images featuring Biron (Earth-One)
- Quotations by or about Biron (Earth-One)
- Character Gallery: Biron (Earth-One)
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