Jordi Chias / Sponge (Mycale acerata) with diver. Lermaire strait, Antarctic Peninsula, Antarctica.

Norbert Wu / Sponge (Mycale acerata) and kelp forest, Palmer Station, Antarctic Peninsula, Antarctica

Norbert Wu / Antarctic Sun Starfish (Labidiaster annulatus), Hydrozoan (Candelabrum penola), and Sponge (Mycale acerata) below kelp forest, Palmer Station, Antarctic Peninsula, Antarctica

Alex Mustard / Orange icing sponge (Mycale laevis) growing on Mountainous star coral (Orbicella faveolata) at an early stage of growth, Cayman Islands, Caribbean Sea.

Shane Gross / Close up of Spiny pink scallop (Chlamys hastata) showing eye detail and Smooth scallop sponge (Mycale adhaerens) encrused on top of shell, Vancouver Island, British Columbia, Canada, Pacific Ocean.

Alex Mustard / Sponge spider crab / Decorator crab (Inachus sp) on Sea vases (Ciona intstinalis). Kinlochbervie, Sutherland, The Highlands, Scotland, United Kingdom. Loch Inchard, The Minch, North East Atlantic Ocea...

Alex Mustard / Sponge spider crab / Decorator crab (Inachus sp) clambers over Sea vases (Ciona intstinalis). Kinlochbervie, Sutherland, The Highlands, Scotland, United Kingdom. Loch Inchard, The Minch, North East At...

Claudio Contreras / Orange icing sponge (Mycale laevis), Guanahacabibes Peninsula National Park, Pinar del Rio Province, western Cuba.

Claudio Contreras / Orange Icing Sponge (Mycale laevis) detail, Cienaga de Zapata National Park, Matanzas Province, Cuba.