Georgette Douwma / Colonial anemones (Amphianthus nitidus) with Green urn sea squirts (Didemnum molle) (Atriolum robustum). Lembeh Strait, North Sulawesi, Indonesia.

Juergen Freund / Green urn sea squirt / tunicate (Didemnum molle) internal detail. Misool, Raja Ampat, West Papua, Indonesia.

Alex Mustard / Sleepy sponge crab (Dromia dormia) climbing over a rock, carrying its sea squirt (Didemnum molle) disguise, with brittlestar. Anilao, Batangas marine protected area, Luzon, Philippines. Verde Island P...

David Fleetham / Tunicate (Didemnum molle), Bali, Tulumben, Indonesia.

Linda Pitkin / Mangrove (Rhizophora sp.), with soft coral (Dendronephthya sp.) growing on the roots, and encrusting tunicates (including Didemnum sp.). Mangrove Ridge, Yanggefo Island, Raja Ampat, West Papua, Indone...

Linda Pitkin / Mangroves (Rhizophora sp.) above coral reef encrusted with tunicates (Didemnum sp.), and Soft coral (Dendronephthya sp.). Mangrove Ridge, Yanggefo Island, Raja Ampat, West Papua, Indonesia.

Linda Pitkin / Pinnate batfish (Platax pinnatus), on coral reef beneath mangroves (Rhizophora sp.). Mangrove roots encrusted with tunicates (including Didemnum sp.), and soft coral (Dendronephthya sp.). Yanggefo Isl...

Georgette Douwma / Colonial anemone (Amphianthus nitidus) and Green urn sea squirt (Didemnum molle) on a gorgonian branch. Lembeh Strait, Sulawesi, Indonesia.

Georgette Douwma / Large sea squirt (Didemnum molle) growing on a sea whip. Mabul, Malaysia. Indo-Pacific.

Aflo / Goby (Gobidae) on tunicate (Didemnum molle) Ishigaki-Jima Island, Japan. July.

Solvin Zankl / Green urn sea squirt / tunicate (Didemnum molle) detail of inner mouth, Raja Ampat, West Papua, Indonesia, Pacific Ocean.

Juergen Freund / A colonial tunicate / ascidian (Didemnum vexillum) invasive species that forms huge colonies, Misool, Raja Ampat, West Papua, Indonesia.