まるです。

まるが今一番気に入っている箱です。
窮屈そうに見えますが、それがいいらしいです。
This is the box which he likes most now.
This is the box which shoes were in.
It seems to be too small for him, but he likes the feeling cramped.

「ぴったりですよ」
Maru:[ This box is very comfortable! ]