Pyura praeputialis is an intertidal and shallow water species of tunicate.

It is the first reported species of marine organism to create a "foam-nest" for its larvae.

[2] Pyura praeputialis is common in coastal areas of the Australian mainland and ranges from southern Queensland to Cape Otway in Victoria.

[3] This species is an ecosystem engineer that can drastically alter habitats by overgrowing other sessile marine invertebrates.

However, the positive impacts it can have are shelter for juveniles that are being hunted, protection from desiccation, beneficial interactions between organisms, and coexistence of other species.