Your Average Anomally

Fiddleford Mcducket!

He's a marbled duck. Was originally gonna make him an Indian runner ducks but these guys have tiny little mullets and it's incredible

him: Quack!

I am not a lawyer so I only have a layman's grasp of this, but as I understand it, if I read a fanfic, think "oh that's a cool idea" and consciously or unconsciously integrate it into my future work, that ensnares me and the fanfic author in a terrible tangle of mutual theft.

Technically, fanfiction exists in an extreme legal gray area, and in the early days of the internet, authors were very litigious towards their fans using their work. In the same way that Disney will get on your ass for putting Mickey Mouse in your work, any author has the same legal ownership of their characters, and they can choose to exercise it. Some famously have, like Anne Rice, but most nowadays do not. Fandom is understood to be a beneficial ecosystem for a creator to cultivate. Most creators Pretend They Do Not See It so it can continue to exist.

But suppose you wrote a fanfic about Aurora where something cool happened, and then a few chapters later, your story showed up in Aurora itself. Maybe even with some lines ripped verbatim, for even less plausible deniability. Oh shit - you've been robbed. But your story was fanfiction to begin with, only loosely permitted to exist with the understanding that you didn't own the setting or characters used. In this scenario, I stole your work, but it was work you made out of MY work in the first place. If you got mad and litigious, the legality of fanfiction itself would immediately take center stage in the argument. Do you have a right to your work when you made it out of MY work without permission? Do I have the right to take work that was made out of my work and use it without credit? The fact that I think fanfiction is a great and fun art form has no bearing on the fact that, technically, it is IP theft. And the fact that it IS IP theft has no bearing on the fact that me seeing a cool idea in a fanfic and going "mine now" would still be a shitty thing to do.

But things can get muddier. Suppose you write an Aurora fanfic where events A, B and C happen, and then over the next several chapters of Aurora, A, B and C happen. Did I steal ideas from your fanfiction? Maybe, but it's also possible that I had A, B and C planned out beforehand, and you put them in your fanfiction because you picked up the foreshadowing and prep I was putting down. You could still be mad about it, but there's a very real possibility that in this scenario the only thing I'd be guilty of was Good Foreshadowing.

In this situation, if you got mad and litigious about it, my best defense would be ignorance. I couldn't have stolen your fanfiction because I never read it. There is absolutely no chance that I was influenced by your work; I've never even laid eyes on it.