Character: comet (dc comics)
Comet the Super-Horse
Pre-Crisis Comet
Comet was originally a centaur from Ancient Greece who was changed by a witch giving him immortality, incredible strength and speed, telepathy, and the ability to shape shift (a sapient horse or a human male). In his human male form as Bill Starr he dated Supergirl (and briefly Lois Lane) and in his horse form served as Supergirl's "pet".
Comet also served as a member of the Legion of Super Pets alongside Krypto the Superdog, Beppo the Supermonkey, and Streaky the Supercat.
Post-Crisis Comet
In 1997 Comet underwent a drastic change in the series. Comet was revealed to have the powers of flight and ice generation powers. It is revealed that Comet is actually a union of Andrea Martinez, a bi-sexual stand-up comic and friend of Linda Danvers (Supergirl) and Andrew Jones, a former (male) jockey who was trampled to death in a horse race and "rebuilt" by an organization calling themselves "The Stable" using gene splicing to combine his DNA with that of an equine.
Andrew Jones rebelled against "The Stable" and began operating as a rogue superhero. Later in an attempt to rescue Andrea Martinez from an avalanche both were killed. The result was a fusing of personalities and the birth of a completely new superhero Comet who was also revealed to be the Angel of Love.