Polyphemus (transliterated as Polyphemos in Robert Fitzgerald's translation), a character in Greek Mythology, is a Cyclops, a son of Poseidon and Thoosa. He also plays a pivotal role in Homer's Odyssey.
Polyphemus in Homer's Odyssey
In the story of Homer's Odyssey, a scouting party led by the Trojan War hero Odysseus lands on the Island of the Cyclopes and ventures upon a large cave. They enter cave and proceed to feast on some food they find there. Unknown to them, this cave is the home of Polyphemus who soon comes upon the trespassers and traps them in his cave. He proceeds to eat several crew members, but Odysseus devises a cunning escape plan.
To make Polyphemus unwary, Odysseus gives him a barrel of very strong, unwatered wine. When Polyphemus asks for Odysseus' name, Odysseus tells him "ουτις," a name which is translated as "Noman" or "Nobody," but which has been used allusively by later authors. Once the giant falls asleep, Odysseus and his men use a spear that had been hardened in the fire to destroy Polyphemus' only eye. He yells out to his fellow Cyclopes that "Noman" ("Nohbdy" in Robert Fitzgerald's translation) hurt him; the others take this to mean that Polyphemus is being attacked by a god, and so they do not intervene. In the morning, Odysseus ties his men and himself to the undersides of Polyphemus' sheep. When the Cyclops lets the sheep out to graze, he feels their backs to ensure the men aren't riding out, but doesn't feel the men underneath.
Once the sheep (and men) are safely out, Polyphemus realizes that the men aren't in his cave. As Odysseus and his men sail away, he boasts to Polyphemus that "Noman didn't hurt you, Odysseus did!" Unfortunately, Odysseus didn't realize that Polyphemus was the son of Poseidon; Odysseus had already earned the enmity of that god, by defiling his temple in Troy and devising the sack of Troy, a city that held Poseidon in greatest esteem (although Poseidon had largely fought on the side of the Greeks during the Iliad). Poseidon causes Odysseus a great deal of trouble throughout the rest of the Odyssey.
Acis and Galatea
The Sicilian Greek poet Theocritus wrote two poems circa 275 BC concerning Polyphemus' love for Galatea, a sea nymph. Galatea rejected Polyphemus in favor of a shepherd named Acis. Jealous, Polyphemus killed Acis with a boulder. Galatea turned Acis' blood into a river of the same name in Sicily. Thus, Acis became river god....
The story of the romantic tragedy of Acis and Galatea has been used in drama and opera (by Georg Friedrich Handel in 1718, with a libretto by John Gay, Alexander Pope, and John Hughes).
Other mythological figures
Additionally, one of the Argonauts was named Polyphemus. He helped Heracles search for Hylas, and both were left behind by the Argo.