Which Tolkien character says the riddle answer “time” in The Hobbit?

Bilbo Baggins gives the riddle whose answer is “time” in J.R.R. Tolkien’s The Hobbit. The riddle appears during the tense riddle-game between Bilbo and Gollum beneath the Misty Mountains.

Bilbo’s riddle asks what devours all things, including birds, beasts, trees, and flowers; wears down iron, stones, and steel; and brings down kings. The answer is time. Bilbo does not present the answer as a simple statement during the game, because he is trying to survive and escape Gollum’s underground island.

Gollum asks Bilbo several riddles, and Bilbo answers many of them correctly. When Bilbo cannot think of a proper riddle, he asks, “What have I got in my pocket?” This unusual question becomes decisive because Gollum interprets it as a riddle.

The answer “time” is sometimes incorrectly attributed to Gollum because he is the other participant in the scene. In the text, however, Bilbo is the character who asks that particular riddle.