Not sure why I felt like a jack-in-the-box picture, except that I think I saw a clip of one of those Tom and Jerry moments when Tom gets accordioned and I liked the pleating in his belly. As to why it's a kangaroo instead of anything else, eh, why not? I didn't have a particular kangaroo in mind, but there's some resemblance to Spunky the Joey, as seen in Spunky the Smiling Spook (and some other comics), eg https://comicbookplus.com/?dlid=24987 from page 23.

Accordion-pleating is a lot of fun to draw and I'm thinking of doing another.

I was feeling all good at being done with this and then realized the handle had to be on the right-hand side of the box and I had to put in a new layer with that.