Maybe Spiderman 2099 discovers a time - traveling device and accidentally brings back a villain from the past. He then has to find a way to send the villain back while dealing with the chaos the villain causes in his time.
One idea could be that Spiderman 2099 has to team up with a group of rebels from a future dystopia to take down a powerful corporation that controls the city. They might face advanced technology and dangerous enforcers.
Another plot could be that Spiderman 2099's identity is finally revealed to the public in a way that causes mass panic. He has to prove that he's a hero and not a threat, while also dealing with new enemies who take advantage of the situation.
Another idea is a time - travel fanfiction. Spider - Man could be sent back in time to when his Uncle Ben was still alive. He would have the chance to prevent his uncle's death, but he'd also have to deal with the consequences of changing the timeline, like how it might affect his own development as a hero.
A cool plot could be that there is a glitch in the game world that starts causing real - world disasters. Spiderman has to figure out how to fix the glitch by going deeper into the game code, all while still dealing with his regular villains.
One idea could be exploring what would happen if Spider - Man had to team up with a villain to stop a greater threat. For example, partnering with Doctor Octopus to take on an alien invasion.
One idea could be that Spider - Man has to face a new villain who has the power to manipulate his darkest fears and turn them into reality. Another could be a version where Spider - Man is wrongly accused of a major crime and has to clear his name while also dealing with the city turning against him.
A story could be set in a future where the worlds of Marvel and DC have merged. Spiderman and Starfire are part of a new superhero team. They have to deal with the cultural differences between their two groups of heroes as well as face off against new villains created by the merger of the two universes.
A different plot idea could be centered around the villains who were sent back to their own universes. What if some of them managed to find a way back to Peter's universe? And this time, they form an alliance, using their combined knowledge of different universes to try and finally defeat Spider - Man once and for all.
An OC in 'ultimate spiderman oc fanfiction' could be a mutant with the power to control plants. They could use their powers to help Spider - Man fight villains in a more environmental - friendly way. For example, they could create giant vines to trap villains or use plants to detect the presence of danger. Another plot idea is an OC who is a master of disguise. This OC could infiltrate the criminal underworld to gather information for Spider - Man, leading to some tense undercover operations. Or an OC who has the power of super - speed and teams up with Spider - Man to take on enemies that are too fast for Spider - Man to handle alone.
One idea could be that they team up to fight a new villain who has the ability to manipulate time. This would put their different powers and personalities to the test as they try to stop the villain before he changes the timeline too much.
One idea could be that Venom and Spider - Man are forced to team up against a new symbiote villain that is far more powerful and malevolent. This new symbiote could be controlling innocent people, and Spider - Man and Venom have to find a way to stop it without harming the hosts.
One plot idea could be that the Avengers discover Spiderman's identity during a mission when his mask gets damaged. Then they have to protect his secret from villains who are also after it.