Perhaps there's a dimensional rift that has opened up due to some experiment gone wrong. Eddie Brock and the symbiote are accidentally sucked into the rift and end up in the Avengers' universe. The Avengers see the symbiote as a potential danger at first. However, Eddie convinces them that he just wants to get back home. Along the way, they discover that there are creatures from the other side of the rift that are planning to invade their world, so they have to work together to close the rift.
One possible plot could be Eddie Brock's symbiote having some sort of connection to a new threat that the Avengers are facing. Maybe the symbiote has knowledge of an alien invasion that's about to happen. So, Eddie Brock teams up with the Avengers to stop it. They might initially be suspicious of him because of the symbiote's wild nature, but over time they learn to work together.
The plot could involve a villain who wants to use the power of the symbiote for his own evil purposes. This villain lures Eddie Brock into a trap and then tries to extract the symbiote. But the Avengers get wind of this and step in to save Eddie. In the process, they realize that they need Eddie and the symbiote's unique abilities to defeat the villain, who has some sort of weapon that can disrupt the Avengers' powers.
Well, Eddie Brock could initially be seen as a threat. His symbiotic nature might make the Avengers cautious. Maybe Spider - Man, if he's part of the Avengers in that fanfic, would have a special reaction since he has his own history with Venom (Eddie Brock).
Iron Man would probably be very curious about the symbiote. He might try to study it at first, which would make Eddie Brock a bit defensive. Captain America, on the other hand, would be more cautious. He would want to make sure that Eddie and the symbiote don't pose a threat to the team or the general public. Thor might see the symbiote as some sort of strange magic or creature from another realm and be ready to fight it if necessary.
The Avengers' reaction would depend on how Eddie presents himself. If he comes in peace, some like Thor might be more open - minded. Thor has seen all sorts of strange creatures in the nine realms, so the symbiote might not seem too outlandish to him. However, Hulk might be more aggressive towards Eddie, seeing him as a potential threat to his 'family' (the Avengers).
One possible plot could be that they face a lot of challenges in preparing for the baby. Maybe they have to find a way to keep the baby safe from Venom's enemies. They might also struggle with how to raise a half - human, half - symbiote child, like figuring out what kind of diet the baby would need.
One good example could be a story where the Avengers are on a mission in New York and they cross paths with Eddie Brock. Maybe Eddie is investigating a symbiote - related crime that turns out to be linked to some alien tech the Avengers are also after. In this fanfiction, the Avengers initially suspect Eddie of being a villain but then realize he's an ally when they find out about his anti - hero nature.
Iron Man's cocky and self - assured personality might clash with Eddie Brock's more gritty and street - smart attitude. Iron Man could see Eddie as a bit of a loose cannon. However, they could also blend well as they are both intelligent in different ways. Iron Man with his technological genius and Eddie with his knowledge of the criminal underworld.
Well, perhaps in this fanfiction, there's a multiverse rift that pulls Nightwing into the Avengers' world. The Avengers initially mistake him for an enemy, but after some misunderstandings are cleared up, they realize his skills. Together, they face a new threat created by a combination of Hydra and some of Nightwing's rogues gallery who have also crossed over. Nightwing could teach the Avengers some stealth tactics while they show him how to handle more powerful cosmic threats.
One possible plot could be that the Shikon Jewel gets scattered across the Marvel universe. Inuyasha and his friends, like Kagome, have to team up with the Avengers to retrieve the pieces. Iron Man might be intrigued by Inuyasha's sword and try to study it, while Captain America could admire Inuyasha's fighting spirit. They'd face villains who also want the power of the Shikon Jewel, creating an epic adventure.
One possible plot could be that the Voltron team gets transported to the Avengers' universe. They might initially be seen as threats, but then they realize they need to team up to fight a common enemy, like a powerful alien force that's too much for either group alone. The Voltron lions could combine in the middle of New York City, creating an amazing spectacle.
A really interesting plot could be a time - traveling crossover. Supergirl goes back in time to the era of the original Avengers. She helps them in a battle that changes the course of history. In return, the Avengers help her find a way back to her own universe. During this time, she forms a special bond with Thor, as they both have superhuman strength and a connection to otherworldly powers.