Golum (sometimes spelled Gollem) is a member of the Tolkien Appreciation Society, dressed as a character from Tolkien's work. He is attending the annual meeting of the society, and it is his duty to get lunch. He is fishing outside the cave (having a fishing licence in a pouch in his costume), and also had The Ring with him but lost it in the river. He made his costume himself.
Simon meets Golum, and after making sure he isn't breaking any copyright laws, is told to help him find lunch. Carrying some of the Swampling's stew in a specimen jar, Simon convinces Golum that it is concentrated Stew de Swamp, capable of feeding 40 people just by adding boiling water. Golum takes the stew into the cave, and lets Simon use his fishing rod. Simon then fishes out lots of junk from the river and eventually finds Golum's lost ring in the river.