Polyphemus

Polyphemus was the giant son of the god Poseidon and Thoosa in Greek mythology. He was one of the Cyclopes, having a single eye. According to the Odyssey, Odysseus arrived at the island of the Cyclops (Sicily), while trying to go back to his homeland, Ithaca.

Polyphemus is the secondary antagonist in Percy Jackson: Sea of Monsters. He is portrayed by Robert Maillet and voiced by Ron Perlman. Unlike in the book, he only takes Grover prisoner after the latter is captured and forced by Luke Castellan's henchmen to lead them to the Golden Fleece.

When Percy and his friends find the Fleece, it turns out that it is hidden in Circeland, an amusement park that Polyphemus's lair is also in (this was done to adapt it into a more modern setting).[1]  Percy learns that Grover has been masquerading as the hideous Cyclops's "bride" in order to find a way to get the Fleece. The heroes successfully manage to snatch the Fleece from Polyphemus.

Later, after Kronos's defeat, Luke is thrown into the Cyclops's lair, where Polyphemus prepares to eat Luke. It is unknown what happens afterward.