

This could explain why, much like Bilbo is not as monstrous as Gollum, the discernibly Hobbit-like Gollum is not as deformed and unrecognizable as the Ring Wraiths. In "The Shadow of the Past," Tolkien explains that Hobbits are less susceptible to the Ring’s powers than humans. This was a chilling reminder of the ring’s corrupting influence which, according to one wild Lord of the Rings fan theory, could have led Gollum to kill Frodo’s parents. He did, however, offer viewers a flash of his monstrous potential when he saw the One Ring in Frodo’s grasp.

As a result, Bilbo did not become a monster like Gollum. In contrast, Bilbo only maintained possession of the ring for 60 years, and he was a lot more careful about its corrupting influence. Gollum owned the One Ring for 500 years, during which time the powerful artifact turned him from an ordinary Hobbit-like creature into a monster.
