In Homer’s Odyssey, the Cyclops who imprisons Odysseus and his crew is Polyphemus.
Polyphemus is the one-eyed son of Poseidon and the sea nymph Thoosa. Odysseus and his sailors enter his cave while searching for food and shelter, but the Cyclops traps them by rolling a huge stone across the entrance.
Odysseus eventually defeats Polyphemus through deception rather than strength. He tells the Cyclops that his name is “Nobody,” blinds him with a sharpened stake, and escapes beneath the bellies of sheep. When Polyphemus calls for help, he says that “Nobody” is attacking him, so the other Cyclopes do not assist.
The episode explains why Poseidon becomes hostile toward Odysseus: the hero reveals his real name after escaping, allowing Polyphemus to ask his father for revenge. Polyphemus is sometimes confused with the Cyclops in later Greek myths involving Galatea, but Homer’s character belongs specifically to the Odyssey.