A person or other being capable of changing their physical form(noun)
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Use "shape-shifter" in a sentence
"Aralorn is a shape-shifter and a spy, sent to determine what is going on with a powerful sorcerer, whose charisma blinds nearly everyone in the surrounding kingdoms to his true (and horrific) nature."
"He belongs, like Borges and a handful of others, to that sacred sect of storytellers (one part sorcerer, one part shaman, one part shape-shifter, one part fabulist) that seem to write in the invisible ink of dream."
"Each thought a slippery trickster, a shape-shifter."