Why God is Not a Shape-Shifter

A couple months ago I was reading a book about Wicca written by a witch. One of the themes of the book was basically an endorsement of pantheism. The author would write the Universe with a capital "u" every time the word came up.

Similarly, the author firmly believed that the Universe, this pantheistic Deity, was a shape-shifter. To be sure, she seems to have a strong case with respect to the universe having shape-shifter like qualities. According to physics, matter is a form of energy. In principle, there is no reason why one form of matter, say a teacup, could not be transformed into another form, say a small notepad. In fact, it is a common belief in some circles that this transmutation of energy from one form to another explains both the after-life and reincarnation. There is a well-established principle in physics known as the "Law of the conservation of energy." Basically, energy is neither created nor destroyed; it is simply reformulated from one form to another. So, many New Agers believe that we humans are basically energy, and when we die our energy simply goes elsewhere; it is not destroyed and they can point to physics to back them up. And with respect to reincarnation, that is simply a case of an individual coming back with his energy in another form. I, for one, find no reason on this view, why an individual might not come back as a rock... and if that happens, isn't he more or less destroyed as far as his consciousness and personality are concerned? What kind of "life" would a rock be said to have?