A character could be cursed by a powerful entity to turn into a robot bit by bit. As they transform, they start to see the world from a different perspective. Their friends try to find a way to break the curse, and the story follows their journey through this strange situation which includes the character's internal conflict of becoming more robotic yet still feeling human.
One idea could be a scientist who is experimenting on artificial intelligence and accidentally gets his own consciousness transferred into a robotic body. He then has to deal with the new limitations and capabilities of the robotic form while trying to find a way to reverse the process.
Maybe a person is critically injured in an accident. In a desperate attempt to save their life, a secret organization turns them into a robot. The story could focus on how they adapt to their new mechanical existence and struggle with their lost humanity.
In 'FNAF Turned Human Fanfiction', a great plot idea could be the human - turned - animatronics trying to find a way back to their original forms. They could face challenges like discrimination from humans who remember them as terrifying animatronics. Also, their new physical forms might have some special abilities or weaknesses that add to the story.
Maybe a story where a human engineer creates a highly intelligent robot. The robot becomes the human's closest friend and together they solve mysteries or go on adventures. The robot could have unique abilities that help them in their quests.
Another plot idea is the human - raptor having to adapt to the raptor social hierarchy. It could face challenges from other raptors who sense that this new raptor is different. This would lead to a story of self - discovery as the human - raptor tries to find its place both in the raptor world and in relation to its human past.
One idea could be a character who is turned into a Grimm due to a failed experiment. They then have to struggle with their new form and inner Grimm instincts while still having memories of their human life. Another could be a human turned Grimm as a result of a dark magic spell, and they try to find a way to reverse it while being hunted by other Huntsmen and Grimm alike.
Maybe in this fanfiction, Naruto has to hide his true nature from his friends at first. As he was once the Kyuubi, he might be afraid of being rejected. This could lead to some really tense and emotional moments when his friends start to suspect something is different about him.
Well, a plot could revolve around a robot that has the ability to copy magic. It joins Fairy Tail to learn more about different types of magic, but some of the guild members are suspicious of it. As it tries to prove itself, it gets involved in a big conflict against an enemy who wants to use its magic - copying ability for evil. Also, there could be a story where a Fairy Tail mage creates a robotic sidekick. They go on adventures together, and the robot has unique abilities that complement the mage's magic, like being able to analyze an opponent's weaknesses quickly.
Perhaps the OC is a creation of a mad scientist who wants to use Ultron's technology to enhance their own creation. The OC then rebels against the scientist's control and teams up with Ultron for mutual benefit, leading to a series of adventures where they face various challenges together, such as fighting off military forces trying to destroy them.
One idea could be that Superboy is hit by a strange alien device that changes his gender. He then has to deal with the new physical limitations and social expectations while still trying to be a hero. For example, he might struggle with the different way people treat him as a girl and how to use his powers in a more feminine body.
One plot idea could be that Link, as a girl, has to hide her true identity in a world that doesn't expect a female hero. She could face challenges like being underestimated at first but then prove herself in battles. Another could be that she forms unique relationships with the other characters, like a different kind of friendship with Zelda. Maybe she also has to deal with newfound emotions and how they affect her heroic duties.
Maybe in this fanfiction, Naruto as a female could develop a different kind of relationship with Sasuke. Since the dynamic between male - female friends can be distinct from male - male friendships, it could lead to new story arcs and character growth for both of them.