What could be an interesting plot for an MLP Avengers crossover fanfiction?

Maybe the Mushroom Kingdom is in trouble. A strange magical force is draining all the power - ups. Mario discovers that this force is linked to Equestria. He travels there and meets Rarity. Rarity is impressed by Mario's unique style and decides to help him. They find out that a corrupted magic crystal in Equestria is causing the problem. So they have to find a way to purify the crystal. Along the way, they face many challenges, like dealing with jealous unicorns who don't want an outsider like Mario interfering in their world.

One possible plot could be that Oliver Queen gets transported to the Avengers' universe. He teams up with Hawkeye, sharing their archery skills and combat tactics. They could go on a mission to stop a new threat that combines the technology of the Arrowverse and the super - powered enemies of the Avengers.

A cool plot might be that the Tailed Beasts in the Naruto world are being targeted by an unknown force from the Marvel universe. The Avengers, thinking it could lead to a greater threat to both universes, come to help. Naruto and the Avengers have to work together to protect the Tailed Beasts. Hulk could have an interesting interaction with the Tailed Beasts, perhaps learning from them how to better control his rage, while the ninjas are amazed by Thor's lightning powers and try to incorporate some of that into their own jutsu.

Perhaps the Joker discovers a way to mind - control some of the Avengers. He targets Hulk first, making him go on a rampage in a major city. The other Avengers are caught off - guard. They soon realize it's the Joker's doing. Spider - Man, who has recently joined the Avengers, swings in to help. He uses his agility to dodge the Hulk's attacks and tries to figure out a way to break the mind - control. Doctor Strange is called in to use his magic to counter the Joker's mind - games, and the team must fight both the controlled Avengers and the Joker's minions to save the day.

Well, perhaps a powerful and mysterious new threat emerges that neither the Punisher nor the Avengers can handle alone. The Punisher has his street - level combat skills and no - holds - barred attitude, while the Avengers have their superpowers and teamwork. They are forced to team up. During the mission, the Punisher has to deal with the Avengers' more heroic and less lethal approach, which causes some friction at first but eventually they find a middle ground to defeat the enemy.

A great plot in this crossover fanfiction might be that an ancient threat from both universes resurfaces. In the HTTYD world, it could be an even more powerful and evil version of the Red Death. In the Avengers' universe, it could be a new group of super - villains. The Avengers and the HTTYD characters then have to combine their skills. The dragons could be used to transport the Avengers quickly across the HTTYD landscapes, and the Avengers could teach the Vikings about modern combat strategies.

One idea could be that the Glitchtale characters are transported to the Avengers' universe. Sans could use his shortcuts to surprise the Avengers, and Betty could be a powerful villain they have to face together. Maybe Papyrus befriends Thor because of their similar jovial natures.

A possible plot could be that the Avengers are on a mission to retrieve a powerful artifact. Deadpool, who has his own reasons for wanting the artifact, also shows up at the same place. Instead of fighting each other, they form a temporary alliance. Deadpool's knowledge of the underworld and his unpredictable fighting style, combined with the Avengers' superpowers, help them overcome the various traps and enemies guarding the artifact. However, after getting the artifact, they have to decide what to do with it, which leads to some internal conflict among the group and more hilarity with Deadpool's input.

One idea could be that Robin, with his detective skills, is investigating a mystery that has ties to the Avengers' world. Maybe it's a series of high - tech thefts that seem to be related to some new villain who has both Gotham - style cunning and super - power ambitions. Robin could team up with Iron Man to analyze the technology used in the thefts. Iron Man would be impressed by Robin's quick thinking and resourcefulness despite not having superpowers.

Well, perhaps there's a threat that can only be defeated by combining the chakra in the Naruto world with the superpowers of the Avengers. For example, Thor's lightning could combine with Sasuke's lightning - based attacks. And Captain America's leadership could inspire Naruto to lead his own team in a new way. They all start off not trusting each other much, but as they face challenges together, they learn to work as one.