Metamorphosis (also known as Shape-Shifting) is the ability to alter one's physical structure into a variety of shapes and sizes. The nature and range of such an ability varies from user to user. This power differs from Transformation, which enables a user to alter his or her physical features into one specific form. The ability to shift from one form to the next is almost always instantaneous requiring only a few seconds of concentration for the power to take effect.
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. Beast Boy for example, can shape-shift into any animal that he can think of, but his skin and/or fur and plumage will always be green in color. Clayface on the other hand, can imitate any living creature and can even compensate for finer details such as density and texture.
Many supernatural creatures possess the power of Shape-shifting. Werewolves are most popularly known as shape-shifters, but their ability is actually just an aspect of Transformation, as they can only shift back and forth between two predetermined forms. Vampires on the other hand, possess true shape-shifting to a limited degree. They can alter their physical structure to assume the shape of a wolf, a bat, and sometimes even a fine mist.