Shapeshifting or transformation is the ability to completely change one's body from one form to another, usually by magic or Applied Phlebotinum. Common in Speculative Fiction, folklore and myths are replete with tales of princes transformed into frogs, gods turning themselves into animals, and so on. Several of these tropes are Older Than Feudalism.

There are a wide variety of ways that this can occur, but thematically it can be sorted into two broad classes:

• Shapeshifting: A character can transform their own body as a special power or ability. Obviously enough, they are called shapeshifters, and often ply their powers for fun and profit (whether good or evil), or simply to trick or play practical jokes on normal folks.
• Transformation: An otherwise non-shapeshifting character has a transformation cast upon them from an outside source (again, usually by magic or Applied Phlebotinum). This is typically Played for Drama; it may be part of a character's backstory, or even form the central conflict within the work. Curses are a popular source here, as it requires the character to go on The Quest to satisfy the Curse Escape Clause. Of course, it can also be a temporary Super Mode. A list of possible causes for transformations can be found here.

See also the Autonomous and Artificial Appendage Index, Disguise Tropes, Illusory Index, and Werebeast Tropes indexes.