What is it?

One night my hubby told me to go in to the garden and look at his handiwork. He had only chopped down my favourite tree - a beautiful walnut. He said it was too big for the garden, and needed to come down. I secretly agreed, but was upset to see it go. Some of the wood went to a chap interested in wood turning, but this lump was left. I propped it up in a corner of the garden as a "feature". I kid myself that it is rather like a wooden Venus de Milo without her head!!