One possible plot could be Sonic accidentally getting hit by a strange energy beam during a battle with Dr. Eggman. This beam could have some sort of mutagenic effect that slowly starts to transform him into a human. As he turns into a human, he has to deal with the loss of his super speed at first. He then has to adapt to living as a human while still trying to protect his friends and the world from Eggman's new threats.
Dr. Eggman would be an obvious choice. Since Sonic is now in a more vulnerable human form, Eggman could see this as the perfect opportunity to finally defeat Sonic and take over the world. He might come up with new devious plans, like creating robots specifically designed to target a human Sonic.
One common element in the Sonic turns into Dark Sonic fanfiction could be the role of antagonists. They might have a hand in triggering this transformation. For example, by manipulating Sonic's emotions or by using some sort of dark magic. Once Sonic becomes Dark Sonic, his relationships with his friends like Tails and Knuckles also change. His friends may try to bring him back to his normal self, which can create a lot of drama and action in the fanfiction.
Sonic turning into a robot in fanfiction could also be a self - sacrifice situation. Suppose there's a powerful energy source about to explode and Sonic, in order to contain it, fuses with some nearby robotic parts. This would give him the ability to withstand the blast but at the cost of his normal form. His friends would be shocked at first but then try to find a way to restore Sonic. It could lead to an interesting adventure filled with emotions and high - stakes situations.
One possible scenario could be that Pikachu is exposed to a strange type of energy. This energy mutates its genetic structure, slowly transforming it into a human form. At first, Pikachu might be confused and scared, not understanding its new body. But as time passes, it starts to learn about human ways, like walking on two legs and using its hands to pick things up.
If Sonic turns into a robot in fanfiction, he might gain new abilities. For example, he could have enhanced strength and more precise control over his speed. However, he might also face problems like being hacked or having mechanical malfunctions. His friends like Tails would have to use their technical skills to help him out.
The fanfiction could go like this. Sonic is on a mission in a spooky, abandoned town. Unbeknownst to him, it's infested with vampires. One of them manages to turn him into a vampire. At first, Sonic is horrified. His appearance changes slightly, with paler fur and redder eyes. He has to learn to live with his new condition. His friends like Tails and Knuckles are confused and a bit scared. However, Sonic discovers that being a vampire gives him the ability to sense danger from afar. He then uses this to his advantage to protect the town and his friends from an even greater evil that's lurking in the shadows. Eventually, he might find a way to reverse the transformation and return to his normal self.
The plot might involve Sonic being turned into a Pokemon by a powerful wizard in the Pokemon universe. As a Pokemon, he retains some of his speed abilities but also has to learn Pokemon moves. He meets a group of friendly Pokemon trainers who help him understand this new world. Together, they enter Pokemon battles against other trainers and gym leaders, all while Sonic tries to find a way back to his own world.
One way a human could 'turn into' Zelda fanfiction is through creative writing. If a person is deeply inspired by the Zelda universe, they can start by imagining themselves as a character within it. For example, they could write about waking up in Hyrule, with all its unique landscapes and creatures. They might describe their experiences, like facing off against Bokoblins or exploring ancient dungeons. By using vivid details and elements from the Zelda games, they can create a fanfiction that is centered around their 'human' self in the Zelda world.
One idea could be that Optimus Prime turns into a human mechanic. He uses his knowledge of machinery from his days as a Cybertronian to revolutionize car repair in a small town. People are amazed by his skills and he secretly uses his new form to keep an eye out for any Decepticon threats.