This word has been used before, but long enough ago new members may not have seen it.
From Brewer:
Proteus (pron. Pro'-tuce). As many shapes as Proteus- i.e. full of shifts, aliases, disguises, etc. Proteus
was Neptune's herdsman, an old man and a prophet. He lived in a vast cave, and his custom was to tell
over his herds of sea-calves at noon, and then to sleep. There was no way of catching him but by stealing
upon him during sleep and binding him; if not so captured, he would clude anyone who came to consult
him by changing his shape, for he had the power of changing it in an instant into any form he chose.

In medicine, syphilis used to be referred to as having protean manifestations, meaning it often
had symptoms suggesting other diseases.