Pyura doppelgangera, the doppelganger cunjevoi, is a tunicate that lives in coastal waters of Australasia attached to rocks or artificial structures.

[1] Genetic data from rapidly mutating microsatellites indicate that the species is native to Tasmania and that all non-Tasmanian populations were introduced through human activities during the period of European settlement.

While the species is rapidly expanding its range in New Zealand (where rocky shore habitat is continuous), the invasion of South Australia has stalled because the region mostly has sandy beaches, and settlement is limited to artificial structures.

Although a difference exists regarding the maximum body size of these closely related species, they are indistinguishable externally.

[1][4] The species is named Pyura doppelgangera after the German word Doppelgänger, which in its narrowest sense means "look-alike" (i.e. somebody who closely resembles somebody else).