Any box, big or small is not safe from the kitties. If there is a box...there will be a kitty in it.
The box is clearly too small...but does she care? Nope. What I wasn't able to get a picture of was Kara in this same box. She's a little bigger than Peanut so she couldn't curl up like Peanut could. Instead she just kind of crouched into it....her sides spilling over like a muffin top.