“Phragmatopoma californica is a marine polychaete that glues bits of sand and seashells together into a protective tubular shell while fully submerged in cold seawater. … In the lab Sandcastle worms will add a variety of particles of the preferred size (roughly 0.5 mm) and chemical characteristics (not plastic) to their tubes [that they create with a glue-secretion]. In this case the tube has been extended with 0.5 mm glass beads. ” Russell J. Stewart. University of Utah