Which character from “The Lord of the Rings” is famous for the phrase: “My precious”?

Gollum is a fictional character from J. R. R. Tolkien's legendarium. He was introduced in the 1937 fantasy novel "The Hobbit", and became an important character in its sequel, "The Lord of the Rings". Gollum was a Stoor Hobbit of the River-folk, who lived near the Gladden Fields. Originally known as Sméagol, he was corrupted by the One Ring and later named Gollum after his habit of making "a horrible swallowing noise in his throat".

Sméagol obtained the Ring by murdering his friend Déagol, who found it in the River Anduin. Gollum referred to the Ring as "my precious" or "precious", and it extended his life far beyond natural limits. Centuries of the Ring's influence twisted Gollum's body and mind, and, by the time of the novels, he "loved and hated it, as he loved and hated himself."