The Mammetum, for all their gifts, appear as oddly formless beings themselves. They seem to constantly shift their features, and many leave after-images of themselves as they move. Others take the opposite route by assuming an androgynous appearance, void of identifying or unique features. The High-Torment Mammetum are not nearly as fluid; their transformations are almost painful to watch and they tend manifest their hatred directly on their bodies in the form of claws, sharp teeth, or other monstrous appendages.
Compared to what the Mammetum could once do with their forms, the modern Mammetum are extremely restricted. Originally, the Mammetum took pride in never taking the same form twice; they constantly shifted their figures and forms to adapt to the situation at hand. They embodied change, and worked with many of the other Houses and Visages to bring that concept to the physical and metaphorical world. The Mammetum were concerned by humanity's fear of change and wanted show them that change could be for the better; after they fell, many wondered if humans would have been better left alone. Many feel weighed down by the slow pace of modern humanity and wish to free themselves, and perhaps the humans, from those restrictions.