It’s October, and Bateman has received in the mail a number of the latest, most expensive pieces of electronic sound equipment. He spends several pages detailing the items and their specific technical capabilities. He’s on the phone debating a charge with his lawyer when he sees, perched on the seat of his toilet, a large rat. The rat leaps from the toilet and scampers to the kitchen where Bateman, unbothered as a result of taking multiple Halcion, tries to catch it with a bag. He goes out and purchases a mouse trap, which he sets with the only cheese he has: a wedge of brie. A day later, he comes home to find the rat trapped but, because of its size, not killed. He traps it in a large hatbox, placing cookbooks on top to prevent it from escaping.
As if his recent killings have put him on a high, Bateman spends his money in a masturbatory fashion, buying expensive items he doesn’t need just because he can, and so he can say he has the latest technology. There have still been some big changes in him, though: earlier in the novel, he would have been disgusted by the thought of a rat being in his perfect and spotless apartment. Now, however, he wants to keep the rat, as if he’s saving it for something.