Well, it could be about a battle where Hulk accidentally knots Tony with his massive strength, like maybe tangling him in some chains or ropes during a fight. Then the story could focus on how Tony gets out of this situation and if there's any change in their relationship after this incident.
In a Hulk knotted Tony fanfiction, perhaps it's a situation where Hulk is under some sort of mind - control and he uses his brute force to knot Tony up in a complex web of metal or something. The plot might then revolve around other Avengers trying to free Tony and bring Hulk back to normal. They would have to figure out how to deal with Hulk's strength while trying to untangle Tony without harming him further.
There could be a new, powerful alien being as the main villain. This alien might have the ability to influence Hulk's mind and make him knot Tony. The alien's goal could be to weaken the Avengers by taking out Tony, who is a key strategist and tech - support for the team. The fanfiction could then follow the Avengers as they try to figure out how to defeat this alien and free Tony from the knot.
Another plot could be that Tony creates a device that can transfer intelligence. He accidentally transfers some of his own intelligence into Hulk. This causes Hulk to become more intelligent and he starts to question his own existence and role in the world. Together, they embark on a journey to find a way to reverse the process while also learning a great deal about each other.
One common theme is the exploration of their differences. Hulk's raw power and Tony's intellect are like two opposite poles, and fanfictions often play with how they can either clash or complement each other. For example, in many stories, Tony tries to use his tech to control or understand the Hulk better.
Well, it could be that Harry Potter somehow gets the powers of the Hulk. Maybe a spell gone wrong during a Defense Against the Dark Arts class that combines his magic with some strange gamma - ray - like magic, and he starts to transform into a green - skinned, super - strong being. He then has to deal with both the wizarding world's problems and his newfound Hulk - like powers.
Well, it could be that Harry, maybe from the Harry Potter world, accidentally gets transported to the Marvel universe where he meets the Hulk. They might start off as enemies because the Hulk is confused by this strange new person. But then, as Harry shows his magic skills, the Hulk becomes intrigued. And they end up teaming up to fight a common enemy that is threatening both their worlds.
Well, perhaps Loki kidnaps the Hulk to use his strength in some scheme against the Avengers. Maybe he wants to use the Hulk to break into a secure location or as a weapon against Thor.
Another common theme is the power dynamics. Hulk's raw power and Tony's technological power can create an interesting dynamic. Sometimes in the fanfictions, they compete in a friendly way, which eventually leads to a deeper understanding and love. Also, the theme of redemption can be present, where they help each other overcome past mistakes or traumas and in the process, fall in love.
A plot could involve Percy being inspired by the Hulk's ability to break free from restraints. So, when he's captured by an enemy, he channels his inner Hulk - fan and uses his knowledge of the Hulk's strength to escape in a very Hulk - like way, smashing through walls or overpowering guards.
Another plot could be a more personal story. Spiderman and She - Hulk start training together. During the training sessions, they learn more about each other's insecurities and strengths. Spiderman might be dealing with the pressure of being a friendly neighborhood hero and She - Hulk could be struggling with her dual identity. Through their friendship, they help each other grow as superheroes and as people.
Well, perhaps in the fanfiction, Naruto has a special mission to another dimension where he meets the Red Hulk. The Red Hulk's brute strength and Naruto's ninja skills are in contrast. They start off as rivals, constantly challenging each other. However, when a common enemy emerges, an ancient and powerful demon that can manipulate both chakra and gamma radiation, they are forced to combine their powers. Naruto uses his Rasengan enhanced with the Red Hulk's gamma energy to defeat the demon in an epic showdown.