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

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.

Alex Mustard / Flatworm (Cycloporus sp.) resting inside a Sea squirt (Didemnum molle) on a coral reef, Raja Ampat, West Papua, Pacific Ocean.

Sergio Hanquet / Green barrel sea squirts (Didemnum molle) on coral reef, Ari Atoll, Maldives, Indian Ocean.

Alex Mustard / Tiny snapping shrimp (Synalpheus sp.) looks out from within sea squirt (Didemnum molle) at night on a coral reef. Piaynemo Island, Raja Ampat, West Papua, Indonesia. Dampier Strait, Tropical West Paci...

Georgette Douwma / Dark red spined brittlestar (Ophiothrix purpurea) with Green urn sea squirts(Didemnum molle). Tulamben, Bali, Indonesia.

Georgette Douwma / Green urn sea squirts (Didemnum molle) on a gorgonian. West Papua, Indonesia.