This bizarre looking sea sponge in the sea grass beds off Edithburgh Jetty reminds me of a a cross between a diseased heart and a human brain.
It really does look like something that has been recently extracted from an animal and dumped on the ocean floor.
Oddly enough this strange looking form is actually an animal after all and will have spent some part of its childhood free swimming in the sea until it chose its permanent home.
Photo: Robert Rath, 'Sponge Bob' 1/160s f/7.1 ISO640 15mm