Glaucus is said to have become a sea-divinity in the following manner. While angling one day, he observed that the fish he caught and threw on the bank, at once nibbled at the grass and then leaped back into the water. His curiosity was naturally excited, and he proceeded to gratify it by taking up a few blades and tasting them. No sooner was this done than, obeying an irresistible impulse, he precipitated himself into the deep, and became a sea-god.
Like most sea-divinities he was gifted with prophetic power, and each year visited all the islands and coasts with a train of marine monsters, foretelling all kinds of evil. Hence fishermen dreaded his approach, and endeavoured, by prayer and fasting, to avert the misfortunes which he prophesied. He is often represented floating on the billows, his body covered with mussels, sea-weed, and shells, wearing a full beard and long flowing hair, and bitterly bewailing his immortality.