Frodo in Book CanonEdit
When Frodo was 33 years old (or, his coming-of-age), his cousin Bilbo Baggins celebrated his 111th birthday party in a rather spectacular manner: by throwing an enormous party and then vanishing to retire and leaving all of Bag End to Frodo. Part of Frodo's inheritance was Bilbo Baggins's magic ring.
This ring was the One Ring of Power, and at the urging of the wizard Gandalf, Frodo sets out on a journey with his friend Samwise Gamgee (and later Peregrin Took and Meriadoc Brandybuck... and STILL later the entire Fellowship of the Ring) to throw this Ring of Power into Mount Doom.
In book canon, Frodo Baggins is a hobbit. This means he is very short, hairy-footed, and somewhat pudgy. His attitude is unsure at times, but very brave and good of heart.
At the battle of Weathertop, Frodo is stabbed in the shoulder by a Morgul Blade and thereafter bears its cold, biting scar. After the end of his journey, he finishes his cousin's book There and Back Again... but leaves the ending for Sam Gamgee when he sails for Valinor. He is described as never being quite right after his adventure.
Frodo in Movie CanonEdit
In the Peter Jackson movies, Frodo is portrayed by Elijah Wood. Frodo's woobie qualities are ramped up, certainly aided by Wood's big doe-eyes and worried pouts. On the whole, Frodo sticks fairly closely to his bookverse characterization, but when the plot departs, so does Frodo. To the end of the movie series, Frodo is far more unstable than he was in the book, to the point of telling Sam to go away.
While Frodo is still a hobbit in the movieverse, he is played by a very pretty actor. Thus, perhaps some of his pudgy hobbitness is lost a little.
Frodo in BadficEdit
Frodo Baggins is not as much of a target for Suefic as Legolas or Aragorn, but it is not unheard of for a golden-haired hobbit-maiden to dance into his life and try to go on his adventure with him, much to the chagrin of Sam. Often, these Sues love Frodo only for his face, due to his portrayal by Elijah Wood in the Peter Jackson movies. These Sues also seem to forget all of the pudgy well-fed-ness and the hairy feet of the typical hobbit. Expect a tiny supermodel, or even a tiny porn star. In the worst case, she may forget that Hobbits are child-sized. Often, this Hobbit Sue is adventurous and a good fighter and generally unhobbitlike. And expect her to completely overshadow Frodo's important role as the Ringbearer.
In Bad SlashEdit
Frodo Baggins and Sam Gamgee are very, very good friends, and support each other to heroic lengths along the course of their story together. Unfortunately, some fangirls take this to believe that the nature of their relationship is romantic or sexual rather than platonic. Four-hobbit orgies are not unheard of. Even less coherent fangirls may ship Frodo and Legolas or Frodo and Aragorn simply because they think the characters look hot together. There is at least some Frodo and Boromir slash — sometimes nonconsensual.