In The Odyssey, Homer's epic poem, the hero Odysseus' main rival is Poseidon. When Odysseus blinds the Cyclops Polyphemus, Poseidon's son, the god of the sea decides to make Odysseus' sea travels really hard. You can get most of the details in Book 1, Book 5, Book 9, and Book 13.
Homer brings the gods into The Iliad as well, which tells the story of the mythic Trojan War. Most of the gods of Olympus take sides in the human war: Hera, Athena, and Poseidon are rooting for the Greeks, while Aphrodite, Ares, and Apollo are fighting for the Trojans.
Robert Browning's creepy poem about a murderer references a statue of Neptune (a.k.a. Poseidon) taming a seahorse. Yep, that sounds like the god of the sea to us. Check out the poem here.
Poseidon entered the Marvel universe in the 1965 comic series Tales to Astonish. His superhero outfit is pretty wild, so be sure to check it out.
Since 2002, King Neptune (a.k.a. Poseidon) has made numerous guest appearances on the SpongeBob SquarePants TV show and also in the movie. He's a bit touchy, especially on the topic of his thinning hair. Watch a sneak peek of Neptune's birthday party here.
Poseidon lucks out in the Percy Jackson series – he gets to be the coolest god of all and the father of the mortal hero, Percy Jackson. Read about The Lightning Thief, the first book in the series, to learn more about this nicer version of the god of the sea.
The Greek gods make it onto the PlayStation in the God of War video game trilogy. The mortal hero of the games, Kratos, butts heads with the gods of Olympus, including Poseidon. Though they are briefly allies, in God of War III, Poseidon appears as one of the bosses (and we all know what happens to bosses in video games.)