SOI CAT THONG is on the third floor, staring intently into the bedroom at the new cat lying in a far corner. I've installed a screen door, and he can't go inside.
Gradually he begins to raise himself, making his body seem bigger and more powerful. Close to five kilos, the big boy continues to stare at the newcomer. I think he says, "I can take him, maybe even kill him".
Then the newcomer rises and walks over to the screen door. Thong gasps, as in "Are you kidding?"
He immediately drops his body to the floor, his head turned away. "I'm tiny and helpless!" he says. "Just a kitten!"
Today, meet the latest member of our household. His name is Phantom, and he weighs eight kilos. Yes, he's nearly twice Thong's size.
Phantom isn't fat. He's an "American shorthair", a breed developed in the US, known for its big bones and sweet face. Males in this breed are normally around six kilos, so Phantom is a bit bigger than the standard.
The boy has other problems. He's 16 years old, and he has arthritis. Otherwise, he's quite healthy, unlike my other senior cats who suffer from kidney and teeth problems.
His previous owner has told the vet that because of the arthritis, he can't walk up and down stairs, also that his kitty litter tray has to be very low, because he can't raise his legs to get into a basin with high sides.
She and her husband are moving to New Zealand, and because of Phantom's age and his painful arthritis, she wants the vet to put him down.
Perhaps she thinks he won't survive the flight to New Zealand or the month-long quarantine in Singapore required for dogs and cats on their way south. Perhaps she thinks it won't be worth the expense since he's already so old.
The vet refuses to kill him, and the owner, in tears, abandons him at the clinic. When the vet asks me to take him, I think, "Why not? He won't live very long, and at least he can have a good life for the year or so he has left."
Compared to Thai cats, foreign breeds have shorter lifespans. While Thai cats can live up to 20 years and beyond, breeds like Phantom's are quite close to the end at 16 or 17 years.
The vet doesn't have Phantom's complete records. Before he comes to me, he's X-rayed to assess his arthritis.
I'm surprised when the vet surgeon tells me the arthritis is "not so bad." It's at the end of his spine near the tail and has started to move to his hips.
"He can still get around," the vet says. "Just don't let him go outside. He can't defend himself from other cats."
In his third-floor bedroom, Phantom is quite safe. The screen door should protect him from the other cats.
The next day, he greets me with a quiet meow. The litter tray I've given him is obviously too small since the kitty litter is scattered all over the floor.
I give him breakfast and then go to the first floor to take care of the other animals. Suddenly, the cats freeze, and the dog begins dancing around.
All by himself, Phantom has pushed the screen door open and come down the stairs. He walks slightly stiffly, but he's walking - talking, too. Later, I find that the boy's tried out every kitty litter tray on his way down, whether the sides are high or low.
Phantom's a mystery, hiding secrets his owner never mentioned. Is she happy, I wonder, that he's still alive?