[Squirrelloid]

Couldn't change his form anymore, but that mostly meant he couldn't become pretty. The only story involving Sauron in a physical fight is Beren and Luthien, and then it involves shapechanging. In fact, afaict he never takes a form substantially larger than man-sized. (I haven't read all the collected notes books that Christopher Tolkien collected, in particular I haven't gotten to the War of the Ring book, but given how the ring and power in general is portrayed by Tolkien, something as vulgar as larger size seems unlikely).