CaT the Cat (The cat named CaT), usually just called CaT, is the pet of Dex Archer from Earth-83.
Beginning life as a mostly ordinary kitten, CaT's one defining trait was that he was the runt of the litter, making it difficult for his parents' owners to find someone that wanted to buy him. As a result, they eventually abandoned the kitten on a random street with nothing more than a small box to protect him from the elements.
Fortunately for the kitten, he was found the next day by Dex Archer, who was taking a shortcut on his way home from school. Dex brought the kitten home, and though the initial plan was to bring the kitten to an animal shelter, Dex ended up adopting it. Unable to come up with a good name, he decided to simply call the cat Cat, and leave it at that.
A couple years later, a fight between Dr. Animo and Ben Tennyson broke out in Dex's neighborhood while he and Cat were outside. Dr. Animo attempted to fire a mutation ray at a nearby insect, but Ben used Chromastone to absorb and redirect the energy away from his target. In doing so, however, he didn't pay attention to where the warped mutation ray was heading, and it ended up hitting Cat by sheer coincidence. Nothing appeared to happen at first (Cat not even reacting to being hit), and Ben handily defeated Animo.
A few days later, Dex arrived back from school to find that the warped mutation ray had finally taken its effect, transforming Cat into a Chromastone and Tabby hybrid. Dex decided to rename cat, giving him his new name by shortening Chromastone and Tabby to simply CaT (obviously not a huge transition for either of them).
Prior to the Animo incident, CaT was a small gray cat of indeterminate breed bearing a Mackerel Tabby coat with black stripes.
After being mutated with Chromastone's DNA, CaT's color scheme changed to reflect this. His fur is now a dark purple, his stripes a bright magenta, and his eyes a teal color. His stripes changed to a more simple pattern, and have a soft glow at all times.
CaT's abilities before the Animo incident were nothing more than you'd expect from your average housecat. Fast, agile, able to see in the dark, etc.
After the mutation, CaT gained the mental capacity to become sentient, and though his vocal cords remain those of a normal cat, he is able to clearly communicate using body language and unique 'meowing' patterns. Aside from emitting a soft glow, it's unclear so far as to how many other abilities, if any, CaT shares with an actual Crystalsapien.
CaT is...well, catty, for lack of a better word. He's sarcastic, rude, has a large ego, and is really your general cat in that department.
Where he differs, however, is in his sheer loyalty to Dex. CaT makes it a point to follow Dex and try to keep him out of trouble, whether it be avoiding a shady alley or hiding from an alien monster. He can't remember much from being a kitten, but he does remember being rescued by Dex, and wants to repay the favor.