Final answer:
Khattam-Shud's physical appearance during shape changes is not described in detail within the context of his original literary source, and therefore cannot be accurately depicted without specific text references.
Step-by-step explanation:
In the context of literature, Khattam-Shud does not refer to a physical object or being that can change its shape in the traditional sense of the property of a two-dimensional form. Rather, Khattam-Shud is a fictional character from Salman Rushdie's book 'Haroun and the Sea of Stories'. As this character does not physically transform in the way a Shedu in Assyrian mythology might, any description of Khattam-Shud changing shape would be a creative or metaphorical interpretation from the text and should be treated as a literary device rather than a literal change in form. Consequently, without a direct quote from the book explicitly describing Khattam-Shud's transformation, it is not possible to provide an accurate depiction of what he looks like when he changes his shape.