Bilbo inadvertently discovered the Ring's power of invisibility as he fled, allowing him to follow Gollum undetected to a back entrance of the caves.

[T 2][T 4] Sméagol later used the Ring for thieving, spying and antagonising his friends and relatives, who nicknamed him "Gollum" for the swallowing noise he made in his throat, until his grandmother disowned him.

He picked up their trail again as they left,[T 5] following them all the way to Rauros, then pursued Frodo and Samwise Gamgee across the Emyn Muil when they struck out on their own towards Mordor.

[T 11] Sam rescued Frodo from the Tower of Cirith Ungol and, dressed in scavenged Orc-armour, the two made their way across the plateau of Gorgoroth to Mount Doom.

Gloating over his "prize" and dancing madly, he stepped over the edge and fell into the Crack of Doom, taking the Ring with him with a last cry of "Precious!"

[T 5] In a manuscript written to guide illustrators to the appearance of his characters, Tolkien explained that Gollum had pale skin, but wore dark clothes and was often seen in poor light.

[T 6] Sam notes that Gollum has two distinct personalities: the sinister "Stinker" and the submissive "Slinker", with a green glint in his eyes showcasing the change between them.

[T 10] Tolkien describes this as the story's most tragic moment, and he claims "Sam failed to note the complete change in Gollum's tone and aspect.

[T 6] He was unable or unwilling to eat the lembas bread Sam and Frodo carried with them, and rejects cooked rabbit in favour of raw meat or fish.

[T 4] Commentators including the theologian Ralph C. Wood,[12] and the critics Brent Nelson,[2] Kathleen Gilligan,[13] and Susan and Woody Wendling[14] have remarked that Sméagol's murder of Déagol echoes Cain's killing of Abel in Genesis (4:1-18).

[T 4] He draws a parallel between Sméagol's asking for the Ring with Fafner's; Déagol refuses, saying "I'm going to keep it", just as Fasolt says "I hold it: it belongs to me"; Sméagol derisively says "Oh, are you indeed, my love", and strangles him, turning by degrees into the wretched creature Gollum, while Fafner sourly says "Hold it fast in case it falls" and clubs Fasolt to death, becoming by degrees a treasure-fixated dragon.

On the other hand, McGregor writes, Siegfried is a hero, Bilbo, an anti-hero; and the shrunken Mime is the most Gollum-like character in Wagner's Ring Cycle.

[16][T 3] A variety of commentators have suggested that Gollum constitutes a "shadow figure" for Frodo, as his dark alter ego ("other self") according to Carl Jung's theory of psychological individuation.

He notes, too, that both Gollum and Gandalf are servants of The One, Eru Ilúvatar, in the struggle against the forces of darkness, and "ironically" all of them, good and bad, are necessary to the success of the quest.

David Callaway, writing in Mythlore, notes that Tolkien, a devout Roman Catholic, had made Middle-earth a place where good and evil are in conflict under an omnipotent god, Eru Ilúvatar: in other words, "his cosmology is Christian".

[T 15] Rutledge comments that the sad story has happened to everybody, trapped, as Christians believe, in "Sin and Death", and states that[21] The genuinely revolting Gollum is central not only to the surface narrative, ... but also to the underlying theological drama.

Callaway calls this "the ultimate heroic self-sacrifice", arguing that Gollum acted "consciously" using "the good fraction in his mind finally overpowering the Ring's evil".

They note that Haggard's tales share many motifs with Tolkien's The Hobbit, including a non-heroic narrator who turns out to be brave and capable in a crisis; a group of male characters on a quest; dangers in caves; a goal of treasure; and return to a happy countryside.

It was (apparently) that of a woman of great age, so shrunken that in size it was no larger than that of a year-old child, and was made up of a collection of deep yellow wrinkles ... a pair of large black eyes, still full of fire and intelligence, which gleamed and played under the snow-white eyebrows, and the projecting parchment-coloured skull, like jewels in a charnel-house.

[22] Like Gollum, she is human-like but distorted to a parody; she is shrunken and extremely old; her large eyes and speech are distinctive; and she is wholly materialistic, with a "terrible greediness and self-referencing" and "the insatiable claims of the naked ego".

[22] They mention also the cultural background of the late 19th century, combining economic recession, fear of moral decline and degeneration leading indeed to eugenics, and a "for-the-moment hedonism" in the face of these concerns.

They have "dull white" skin with a "bleached look", "strange large grayish-red eyes" with "a capacity for reflecting light", and run in a low posture somewhere close to all fours, looking like "a human spider", through having lived for generations underground in darkness.

[25] Gollum's first known screen adaptation is in Gene Deitch's 1967 short film The Hobbit, where his role is reduced from the action described in the novel to appearing in a single scene which depicts him sitting in his boat.

[27] In Ralph Bakshi's 1978 animated film adaptation of The Lord of the Rings, as in the 1981 BBC radio dramatisation, Gollum was voiced by Peter Woodthorpe.

[29] In the Soviet-era television film Сказочное путешествие мистера Бильбо Бэггинса, Хоббита (The Fairytale Journey of Mr. Bilbo Baggins, The Hobbit) of 1985, a green-faced Gollum is portrayed by Igor Dmitriev.

[34] Variety reported that "he's speaking Russian, sports orange eye-shadow and has what appears to be bright green cabbage leaves pasted to his head.

[35] In Peter Jackson's The Lord of the Rings film trilogy, Gollum is a CGI character voiced and performed by the actor Andy Serkis.

[39] David Bratman however wrote "How much greater Sméagol's agony is in the book, how much more moving and better-written than the films", arguing that Tolkien's account of Gollum's being "in two minds about his role" is more appropriate than what he considers Jackson's unsophisticated dialogue, with its thrice-repeated "Leave now and never come back".

"[3] She comments that the "subtle combination of framing, camera movement, editing, and character glances" requires frame-by-frame analysis to understand in full how Walsh's direction of the scene (to Jackson's instructions) manages "to suggest the conflict between Gollum's two sides".

[51] Gollum appears in a 1989 three-part comic book adaptation of The Hobbit, scripted by Chuck Dixon and Sean Deming and illustrated by David Wenzel.