What is Domo-kun made of?

My assistant manager and I have been wondering about this for quite a long time. We both agree that Domo-kun is a poop monster but often, people will tell us he is not made of poop. However, they are never able to tell us what he is made out of. I’ve looked at Wikipedia and a number of pages devoted to Domo-kun and not one actually says what he’s made out of. Can the fluther community enlighten me?