Perhaps Hulk is in a state of extreme rage that he can't control. He might accidentally target Spiderman. Let's say there was a big explosion in the city that made Hulk go into a wild rage, and Spiderman just happened to be in the wrong place at the wrong time, so Hulk lashed out at him.
One reason could be a misunderstanding. Maybe some villain has tricked Hulk into believing Spiderman is a threat. For example, the villain might have faked some evidence to make it seem like Spiderman was planning something bad against Hulk or his friends.
It could also be due to mind control. There are many powerful villains in the Marvel universe who can control minds. If Hulk was under the control of such a villain, he might be forced to attack Spiderman without really wanting to. For instance, the Puppet Master could use his powers on Hulk to make him do his bidding.
He might also use his webs to his advantage. He could try to web up Hulk's hands or feet to slow him down. Or he could create a web shield to block some of Hulk's attacks. For example, if Hulk throws a big rock at him, Spiderman could use his webs to create a net to stop the rock.
Maybe Wolverine is being mind - controlled. In some fanfictions, villains use mind - control devices or powers to make heroes act against their will. So, he might not be in his right mind when he decides to hurt Spiderman.
In some fanfictions, Tony might help Spiderman by providing him with advanced technology. For example, he could give Spiderman a new suit with enhanced features like better web - shooters or stronger defense mechanisms. This would help Spiderman in his battles against various villains.
Spiderman's agility and web - slinging abilities could be combined with She - Hulk's super strength. For example, Spiderman could use his webs to create a net and She - Hulk could throw it with her great strength at enemies. Or Spiderman could swing She - Hulk around to gain more momentum for her attacks.
He could lose his friendship with Spiderman, if Spiderman survives. Their relationship would be severely damaged, and it would be hard to repair the trust between them.
One possible plot could be that they have to deal with the media frenzy. Spiderman's identity might be at risk of being fully exposed because of his new high - profile relationship with She - Hulk. They could also team up to fight villains who target them specifically because of their union, like a villain who wants to use their combined powers for evil.
One possible reason could be that Tony initially misunderstands Spiderman's actions. He might think Spiderman is doing something wrong when in fact he's not, and then later realizes his mistake and tries to make it up by helping him. For example, if Spiderman is involved in a situation where it looks like he's causing destruction, but it's actually part of a bigger plan to stop a greater evil.
Well, in some fanfics, it could be a power struggle within the team. Spiderman might have new powers or knowledge that the other Avengers are jealous of or afraid of. So, they might take actions that end up hurting him, like trying to isolate him or directly attacking him in a fit of rage or fear.
There could also be a plotline where they both enter a mysterious tournament. They have to fight other superheroes and villains in a series of battles. Along the way, they learn more about each other's capabilities and form a stronger bond.
One common theme is the contrast between their powers. Hulk has raw strength and Spiderman has agility and webs. Fanfictions often play on how they can complement each other in battles.