This coming Christmas, I would like to make a 3D cake in the shape of a cartoon kangaroo for my work's Christmas party. I was planning on making at least 2 cake mix extenders. Does anyone have any suggestions on how to construct something like this? The main thing I'm worried about is how to make the arms because I would like them to extend (if possible) and the kangaroo will have boxing gloves on his hands.

I'm assuming I would need some sort of support for the cake. Maybe screw a wooden dowel in the middle of a masonite board? Where would I find a big enough dowel for that? I'm still not sure how to go about doing the arms and stabilizing them.