Symbolism, Imagery, Allegory
Karl's cat, Hairball, means well. He really does. While he may be the infamous "beds***ter" (21.1) who uses Karl's sheets as his own personal litter box, he's still kind of cute. Seriously, he makes wittle noises like "Qrph" (22.90) and rolls around on his back and lets people rub his wittle tummy. Squee. How can you not love him?
Because he poops on beds, you say. Oh, technicalities.
Anyway, Hairball spends most of the book lurking in the shadows, slinking out every once in a while to, well, you know. But on Sunday afternoon, he emerges to play a semi-pivotal role in the story when Karl catches him doing his thing and decides to take Darla up on her offer to have sex after watching him kill a cat. (Yeah, we know, it's weird.) It's a surefire deal: Whack the kitty, lose his virginity, and as a bonus, lose the poop on the bed.
Except something goes wrong. The more Karl pets the cat when he arrives for his date with Darla, the more he realizes he can't go through with it. "Imagine all the bad parts, and then ask if you'd pay that much to have all the bad parts on purpose, to have the good parts," Karl says. "How many times would I wash my sheet while dead exhausted to have this big hairy idiot purring and loving me?"
We could say Hairball is just a cat and leave this right where it is. Or, we could say something else—that he's a part of Karl's realization that getting rid of the people (and animals) who love you isn't going to make your life better. Just as he realizes he can't kill Hairball, Karl also learns that he desperately needs the Madmen. And Gratz. And Lightsburg. Life may be a mess—like cat poop on clean sheets—but you can always clean it up.