Because he repeated to go to the cat litter again and again in vain...
The vet said it wasn't constipation, just some poo stuck around his archo and plugged it. So, there were not so many poo in his bowel.
Let me show you some of my 4koma (about my life with cats).
Nao-p is my nick name my friend Mami Tachibana gave me. And I call her Mami-p. Of course it comes from Wedding Peach "Momo-p". No one calls me by the name except for her, but I love the 4 koma cartoon "Go Go Momo-pi (Gan-bare Momo-p)"(In the paperbacks) so I use it. :)
Oh, I'm a manga artist Nao Yazawa, and author of Wedding Peach, by the way. :)
These "comic strips" come from my 4-koma blog (in Japanese). You can see all of them in original here. If you have a request which 4koma will be next, tell me. :D
Other Japanese blog