When we picked up Comet from the Salem shelter, he was barely weaned -- they claimed that he was six weeks old, but I doubt that. He was a teacup cat, small enough to fit in the palm of my hand, and almost unbearably cute.
He took ownership of his environment quickly. His second night home, he somehow got up to our bedroom -- I still don't know precisely how, given that he was smaller than any one of the steps up to it. This was his house, and his people, and he was going to get to know all of it.
His early fearlessness did get him into trouble occasionally, as in the night a couple of weeks later when he woke me up -- by sitting on my face. Startled awake, I launched him clear across the room, scaring the heck out of both of us; fortunately, kittens bounce. It did teach him to be careful around me when I'm trying to sleep, probably a good lesson in later years.
The ground floor of our apartment had a circular layout: the living room had an archway to the kitchen on the left, and to the stairway landing on the right, and the kitchen and landing had a doorway between them. The resulting island in the middle had the TV set in it, and he was very fond of running around and around the island at high speed. The resulting (and endlessly amusing) elliptical orbit was where he got his name, which stuck even after he slowed way down.
He grew, and grew, and grew. If he had been a stray, he would have been an enormous and rangy alley cat; as it was, he achieved nearly Klibanesque proportions, around 21 pounds at his peak. But he was never a round cat -- he was large enough to mostly pull it off, save for the huge hanging gut when he walked. I always fancied that he looked rather like a dwarf saber-toothed tiger.
He liked to fancy himself the alpha cat of the house, although it was never entirely true. His brother is something of a gamma, not so much competing with Comet for dominance as ignoring it. They fought a fair amount (usually more good-naturedly on Merlin's part than Comet's) -- Merlin was always the better fighter, but could never entirely overcome the fact that Comet was in a different weight class.
The alpha-cat thing arose more when dealing with humans. Anyone he could cow, he did -- he did a distressingly good job of terrorizing several of the people who came to feed him. He was the classic mercurial cat, affectionate until he decided to rip your hand off. But he never did so with me: he learned early on that I was the real alpha cat of the house, and he respected that. So, for instance, I was the only one allowed to play with The Tail of Doom: he may not have always liked it, but he knew that my reflexes were faster than his, and I did not tolerate getting scratched.
He was territorial to a pretty high degree. He put up with his little brother, but that was the only other animal allowed in the house. Whereas Merlin is unusually social for a cat, always coming to the door or window and flirting with any other cats that might wander by, Comet was always concerned that they would try to come in. So we got into the habit of quietly distracting Comet if Merlin was talking to someone, so that they wouldn't get scared off. He was also fairly territorial around humans, but only with one or two of them -- he had a limit of about two strangers before he would freak out and hide. He never quite had Merlin's social streak in any respect, but he was good when we were alone.
He was a strict indoor cat; that was part of the terms from the Shelter, along with getting him neutered. We occasionally let him wander the front yard on a leash, but he got pretty agoraphobic over the years. The only time we ever tried taking him anywhere outdoors was to Boredom War one year. That was a complete failure: he spent the entire weekend cowering in the tent, and we wound up with a lattice of fine pinholes in the floor of our 10 x 14 foot cabin.
His final year was mostly a pretty good one. His first illness was hyperthyroidism (which I gather is common in older cats); that kicked his rather slow metabolism up a bit, so that he shed a few pounds and actually got much healthier and happier for a good while. Even after we began to treat that, his weight stayed at a good level for much of a year, neither excessively fat as he had been, nor terribly thin. For much of that year, I think he was actually happier than he had been for a number of years previous -- losing the weight made him much calmer and friendlier.
But the weight continued to gradually slide downwards, and they eventually found a mass in his abdomen a few months ago; given his age and condition, surgery didn't seem practical. So since then we've known that the end was coming, and have focused on keeping him comfortable. At the end he was still alert and okay, but basically down to skin and bones -- perhaps 7 or 8 pounds, down to a third what he'd been a couple of years before.
I'm still wrestling with the grief, and probably will be for a while: it's new to me, a shiny and sharp emotion, razoring its effects in. But it helps a bit to remember Comet as he was for most of his life: a bit fat, a tad defensive about his place, but a good lap cat on a cold night...