The animatronics in FNAF have a complex and creepy backstory. They are believed to be possessed by the spirits of children who met tragic ends at the location where the game takes place.
One great FNAF female animatronics fanfic is 'The Secrets of the Girls'. It delves deep into the backstories of the female animatronics in a very engaging way. The characters are well - developed and the plot is full of mystery.
In a crossover fanfiction, the interactions would be really interesting. Ford, if he were involved, would be very intrigued by the animatronics. He might study them to see if they are related to any of the other interdimensional beings he has encountered. Dipper would be the voice of reason, warning everyone about the potential danger. Mabel would try to find the good in the animatronics, perhaps believing that they are just misunderstood. Soos would be the comic relief, making jokes about the animatronics' appearance. Wendy would be the tough one, ready to fight if necessary. The animatronics themselves might be confused by the Gravity Falls gang. The ones that are more aggressive might see them as a threat, while the more docile ones might be curious about these new visitors.
Well, the female animatronics often have unique designs. Their appearance can be both beautiful and a bit spooky at the same time. Fanfic writers can play around with these aesthetics in really interesting ways. For example, they can create stories where the appearance of the animatronics has a deeper meaning or power. Also, they can explore different personalities for these characters that might not be explored in the original game, which gives more depth to the FNAF universe.
One interesting fanfiction could be about a female animatronic who has a hidden past and tries to protect the kids in the pizzeria instead of harming them. Maybe she was programmed differently by a kind-hearted technician.
Freddy is often a popular character. His human animatronic form might be depicted as having a mysterious past, like he was once a normal human who was transformed into an animatronic against his will.
One interesting concept could be the backstories of the human animatronics. For example, how they came to be in the form of animatronics. Maybe they were part of some experiment gone wrong in a spooky pizzeria.
To develop Mike, you could make him start off as a very skeptical person about the animatronics. But as he spends more time with them, he starts to see them in a different light. You can show his internal struggle between his rational thinking and the strange things he experiences with the animatronics. Regarding the animatronics, each one can have a backstory. Chica might have been programmed with a motherly instinct, and as she gets to know Mike, she tries to 'care' for him in her own animatronic way. This helps to flesh out their characters.
Some animatronic hybrids in fnaf fanfic might interact with the original animatronics in a hostile way. They could see the originals as a threat to their existence or as inferior beings. For example, a powerful hybrid might try to dominate the area where the original animatronics are, leading to conflicts.
One plot idea could be that the animatronics initially see Mike as a threat but gradually come to understand his good intentions. Maybe Mike has a special ability that allows him to communicate with them in a unique way, leading to a series of adventures where they have to work together to solve a mystery in the pizzeria. For example, they might be trying to figure out the true origin of the strange occurrences in the building.