What is the name of the creature who guides Frodo and Sam through the Dead Marshes in the Lord of the Rings universe?

In J.R.R. Tolkien's The Lord of the Rings, the creature who guides Frodo and Sam through the treacherous Dead Marshes is named Gollum. Gollum is a small, wretched creature who was once a hobbit named Smeagol, but was transformed by his long possession of the One Ring. Despite his earlier attempts to steal the Ring from Frodo, Gollum ultimately serves as their guide through the Dead Marshes and to the Black Gate of Mordor.

The Dead Marshes are a desolate and dangerous area of swampland that lie on the eastern side of the River Anduin, and are haunted by the dead of an ancient battle. Gollum leads Frodo and Sam across the marshes by a winding and treacherous route, warning them of the dangers that lurk beneath the waters. During the journey, Frodo briefly glimpses the faces of the dead beneath the water, and feels the pull of their despairing voices.