Shapeshifter
Shapeshifter is a term used to describe creatures which are able to change from one form to another.
Examples of shapeshifters
- The Founders in Star Trek
- Skynet T-1000 Terminators from The Terminator and its sequels
- Clawdites in Star Wars
- Werewolves (albeit with a limited number of alternate forms)
- Vampires, in some stories.