Is fan fiction evil? It's not new, that's for sure, and some highly regarded work has been based on earlier literature, borrowing from Shakespeare, the Bible, the adventures of Sherlock Holmes, Charlotte Brontë, Beowulf, and Gulliver's Travels. Why? Borrowing characters or situations allows you to enter into the imaginative world of another writer, to understand that particular world, and to build from it. So don't be ashamed, whether you're inspired by Milton's Paradise Lost or Lost in Space. If you prefer to write an original story, here's a few ideas.
• This is a sword and sorcery story about a Viking who believes he has met Odin — or at least a being with great talents in magic and death.
• This is a first contact humorous novella (with recipes) about a silicon-eater who has come to Earth in search of gourmet opals.
• This is an urban ecological horror story in which vampires deal with the problem that their ability to navigate while in bat form is compromised by the electromagnetic fields from cellular telephones.
— Sue Burke