Metamorphoses Book 13: Acis and Galatea
Galatea loved Acis, the son of a river, and Polyphemus loved Galatea. One day Polyphemus was singing of his love for Galatea and her indifference to him. He sang "'Why prefer you Acis' arms to mine? / Acis may please himself and please, alas, / You, Galatea. Give me but the chance, / He'll find my strength no smaller than my size. / I'll gouge his living guts, I'll rend his limbs / And strew them in the fields and in the sea.'" Book 13 -- Acis and Galatea, line 863-8 When he'd finished his song, he caught his love with Acis. She fled to the sea, and the Cyclops crushed Acis with a huge rock. Galatea changed her dead love to a river god.
After she told Scylla the story, Galatea and the sea-nymphs swam away.