What are some interesting ideas for a 'Stranger Things x Marvel' fanfiction?

One idea could be that the Demogorgon from Stranger Things somehow enters the wizarding world of Harry Potter. The students at Hogwarts have to use their magic to fight it. Another idea is that Eleven has some sort of magical connection to the wizarding world and she gets a letter from Hogwarts. Maybe she could learn magic there and use her powers in combination with spells.

One idea could be that the Demogorgon from Stranger Things somehow ends up in Derry from It. The Losers' Club and the kids from Hawkins could team up to fight it. They would have to combine their different skills and knowledge of the supernatural.

One idea could be that the Losers' Club from 'It' somehow ends up in Hawkins, Indiana, during the events of 'Stranger Things'. They could team up with the kids from 'Stranger Things' to fight a new, combined threat that has elements of both the Upside Down monsters and Pennywise's terrors. For example, the Mind Flayer could merge with Pennywise in some way, creating an even more terrifying entity.

One idea could be a crossover where the ninjas from Naruto enter the Upside Down in Stranger Things. They use their jutsu to fight the strange creatures there. Another could be characters from Stranger Things learning chakra control in the Naruto universe. Maybe Eleven could use her powers in combination with Naruto's Rasengan.

One idea could be that Naruto characters are transported to the Upside Down in Stranger Things. They use their ninja skills to fight the strange creatures there. For example, Naruto could use his Rasengan against the Demogorgon.

You could have an OC that is a transfer student from a different town where strange things have also been happening. This OC could have some knowledge about the otherworldly events that the kids in Hawkins haven't encountered yet. Or make an OC who is a scientist's assistant, secretly helping the main characters by providing inside information from the lab. They might also be in danger because of this connection to the scientific side of the mystery.

Well, one plot could be that Eleven discovers a new power that only Mike can help her control. It makes them have to spend a lot of time together in secret, away from the others. This creates a really close and intense bond between them as they figure out this new aspect of her abilities.

A cool plot could involve the Demogorgon from Stranger Things being somehow related to It. The Losers' Club and the kids from Stranger Things have to figure out this connection and stop both threats. The Losers' Club could share their knowledge of facing supernatural horrors with the Stranger Things kids, and vice versa. For example, Dustin's knowledge of science might help in understanding the nature of It, while Bill's leadership skills could inspire Mike Wheeler.

Another concept is to have the Upside Down merge with the Halloween spirit world. Characters from Stranger Things might find themselves in a strange hybrid world where normal Halloween monsters like vampires and werewolves co - exist with the Upside Down creatures. They would have to figure out how to survive and if there's a way to separate the two worlds again.

One idea could be that a character travels back in time to prevent the initial opening of the Upside Down. They could change a key event that led to all the chaos in Hawkins. For example, if they stop Eleven from using her powers in a certain way that originally weakened the barrier between dimensions.