Which of Poseidon's sons did Odysseus kill?

Odysseus killed Polyphemus, the Cyclops, who is one of Poseidon's sons. In Homer's "Odyssey," Odysseus and his men become trapped in Polyphemus's cave, and to escape, Odysseus blinds him. This act enrages Poseidon, leading to further challenges for Odysseus during his journey home.