Spicules are microscopic structures of hard crystal material with fantastic shapes unique to the different species of sponge. They are part of the skeleton that helps give the sponge its shape. [1:59]

Along with other microscopic organisms (dinoflagellates, diatoms, bacteria, etc.), we become a tiny particle and are pulled through the canals of a sponge. Along the way we learn that sponge cells catch food and make spicules(microscopic...