- This article is about the sea deity. For the king, see Proetus.
Proteus is the name of a sea deity, sometimes portrayed as the son of Poseidon. He is depicted as an old man and a seal-herder. Like other sea gods, such as Pontus and Nereus, he could predict the future, but would only reveal it to a mortal if forcefully compelled to do so. He could, like other sea gods, change his shape.