Short answers, pulled from the story.
J. R. R. Tolkien introduced the character Gollum into the world of The Hobbit in 1937. This small slimy creature lived on an island in an underground lake beneath the Misty Mountains.
The creature originally bore the name Sméagol before his corruption twisted him into the being called Gollum. He strangled his relative Déagol to take possession of the Ring and subsequently lost his family's approval.
More than five hundred fifty-six years had separated their meeting from the day Sméagol killed Déagol. He was almost six hundred years old yet looked like a starved frog or a tailless black squirrel by that time.
Scholars have compared Gollum to the shrivelled hag Gagool found in Rider Haggard's 1885 novel King Solomon's Mines. William N. Rogers II and Michael R. Underwood noted that both characters rejoice in blood and death.
Andy Serkis performed Gollum using motion capture technology in Peter Jackson's live-action film trilogy starting in 2001. Animators built the CGI character around Serkis's facial features, voice, and acting choices for The Two Towers released in 2002 and The Return of King in 2003.