One evening, Sam thought he saw a log floating along behind them. But it wasn't a log, as it had eyes and paddle feet. When he sat up and rubbed his eyes, though, it was gone.
When he told Frodo that night, Frodo told him how he had seen a strange creature following them on the northern borders of Lorien. He feared it might be Gollum.
That night when he was standing watch, Frodo saw a dark shape float up. A whitish hand reached up and grabbed the side of one of the moored boats, and two pale eyes shone coldly as they peered inside. Frodo stood up and drew Sting from its sheath. With a splash the dark shape shot away downstream into the night.
Roused by the sound, Aragorn sat up and asked Frodo what it was. "Gollum," answered Frodo. "Or at least, so I guess."
Aragorn said that Gollum had been following them since Moria, but that he had not been able to capture him. They would try to lose him the next day.
After several days the river narrowed and ran into a gap between tall cliffs. Great pillars rose like towers on either side of the entrance, and as they neared Frodo saw that they were carved into the figures of two great kings.
"Behold the Argonath, the Pillars of the Kings!" cried Aragorn. "Long have I desired to look upon the likenesses of Isildur and Anarion, my sires of old. Under their shadow the heir of Elendil has nought to dred!"
The passage between the cliffs led them to the lake above the great waterfall Rauros. Their journey by water was at an end.
