Bilbo Baggins encounters Gollum beneath the Misty Mountains in J.R.R. Tolkien’s The Hobbit.
After becoming separated from the Dwarves, Bilbo finds a small ring in an underground passage and meets Gollum beside a subterranean lake. The two engage in a riddle contest, and Bilbo eventually escapes by using the ring’s power to become invisible.
Gollum was originally a Hobbit-like being named Sméagol. The One Ring had corrupted and prolonged his life, and he had lived in darkness for centuries before Bilbo found him.
The Hobbit first presented Gollum as a mysterious, dangerous cave-dweller. Tolkien later revised parts of the book so that its account of the Ring better matched the darker history revealed in The Lord of the Rings.