Not to be confused with the movie, the book version of The Fellowship of the Ring includes several scenes with the mysterious, and quite possibly brain damaged, Tom Bombadil.
On the positive side, Tom saves the hapless hobbits twice: first from Old Man Willow, an ancient and malevolent tree that lives on a toxic mix of Highballs and lost Halflings; and then, from a number of barrow-wights, evil soul-sucking undead creatures, not to be confused with Barry Wights, who are excellent, soulful (and unfortunately regular dead) singers of sexy songs.
Speaking of song, Tom spends much of his time in a whimsical and poetic dreamscape of his own construction, singing as he passes blithely through the Old Wood. Tolkien tells us that he dresses in yellow boots and a blue jacket, leaving one to wonder if the author just forgot to mention if Tom was wearing pants, or if he is simply glossing over the lack of pants. I suspect that latter, because he does tell us that Tom has a long brown beard, bright blue eyes, and an extremely red face.
Red face? Is Tolkien suggesting Tom is an alcoholic? It’s hard to say. He acts kind of inebriated, given his propensity to speak in the bizarre poetry of a metre that is at best unconventional, and at worst, deranged. He also likes to talk about himself in the third person. This does not seem to annoy his wife, Goldberry. (Who may or may not be the spirit of the river Withywindle, but who is definitely some kind of saint for putting up with this narcissistic and enigmatic half-wit.)
Bombadil is totally unaffected by the Ring, and he demonstrates this by doing a little sleight-of-hand, taking the ring from Frodo, and making it disappear in the air. (I suspect he palms it, but again, Tolkien does not tell us directly.) The One Ring doesn’t make him invisible, and he doesn’t seem to be influenced by Sauron through it.
So why don’t they just keep the ring hidden with Tom? It would have saved Frodo a painful stab-wound, massive existential angst, and having to endure Sam’s repeated attempts at innuendo, by suggesting that he could really go for a nice bit of “cony stew.”
Apart from the fact, that, hey, no trilogy, Gandalf suggests that because Tom is unaffected by the ring, he would probably not consider it important enough to protect. That’s a nice way of saying he’s a flighty (possibly pantsless) wanker.