Sometimes called "shape shifting", Metamorphosis is a term used to describe the ability of some characters to alter their physical structure into a variety of shapes and sizes. It differs from Transformation because the user is not limited to one form or a direct form.
In many cases, the shifter in question can alter their form to mimic the physical characteristics of people or animals. Some shape shifters can mimic another's form down to the molecular level, while others may be hampered by certain restrictions. Shapeshifters, as a whole, can be further classified into different groups that are related to the forms they can change into: Metamorphs (limited to human forms, unable to change mass), Animorphs (take on animal forms and may be able to take on the abilities of the altered form), and Polymorphs (who can assume any form, size, mass and appearance at will).