Protean (adj.)

"of or pertaining to the Greek sea-god Proteus," 1590s, from Greek Prōteus, son of Oceanus and Tethys, who could change his form at will; hence, "readily assuming different shapes, exceedingly variable." His name is literally "first," from prōtos "first" (see proto-).

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Definitions of Protean from WordNet

protean (adj.)
taking on different forms;
eyes...of that baffling protean grey which is never twice the same