The creature originally called Sméagol in J.R.R. Tolkien’s The Lord of the Rings is Gollum.
Sméagol was a member of a river-dwelling people related to hobbits. On his birthday, he discovered the One Ring after Déagol found it in the Anduin. Sméagol murdered Déagol to obtain the Ring, and the Ring’s influence gradually isolated and transformed him. His repeated swallowing or choking sound led others to call him Gollum.
Gollum lived for centuries in the Misty Mountains, hiding from sunlight and other creatures. Bilbo Baggins encountered him during the events of The Hobbit and won the Ring after their riddle contest. Gollum later pursued Bilbo’s heir, Frodo, and became both an enemy and an unwilling guide.
The character is central to the Ring’s destruction because his desire for it ultimately carries him into Mount Doom. His divided identity is one of Tolkien’s clearest studies of corruption, pity, and moral choice.