One idea could be that Sharkboy and Lavagirl find themselves in a new dimension where they meet characters from another story. They have to team up with these new characters to defeat a common enemy that threatens both their worlds. For example, they might encounter a powerful ice - themed villain who is freezing over all the water in their world and the new world they've entered. Sharkboy's ability to control water and Lavagirl's heat - based powers would be put to the test as they try to stop this villain.
Maybe they could time - travel in the fanfiction. They end up in a time when their powers are not fully developed yet. They have to quickly learn how to use their nascent powers to face a danger that has followed them through time. This could also involve them meeting their younger selves and teaching them how to better control their powers. It would be a great opportunity for character growth and exploration of their backstories.
The fanfiction could start with the birth of the baby. It's a moment of joy for Sharkboy and Lavagirl, but soon they realize that the baby's presence is causing some unexpected changes in their world. For example, the baby's power fluctuations are affecting the balance between the shark and lava realms. They need to find a way to stabilize this. Meanwhile, they also have to deal with the fact that their baby is growing up in a world that might not accept it easily due to its unique nature. So they work together as a family to overcome these difficulties and create a safe and loving environment for their baby.
An interesting plot could be an OC who is a tech - genius and creates new gadgets for Sharkboy and Lavagirl. For example, a device that can enhance their powers or help them travel faster. The OC could also have a personal vendetta against a villain who is using technology to disrupt the balance in their world. This would lead to a story where the OC, Sharkboy, and Lavagirl team up to defeat the high - tech bad guy. It could involve a lot of action - packed scenes in a high - tech city or a secret lair.
A cool Sharkboy and Lavagirl fanfiction could be that they swap powers for a day. It would be really interesting to see Sharkboy trying to control lava and Lavagirl swimming around as a shark. Or perhaps a story where they meet other kids with similar but different elemental powers and they all form a team to protect a magical place that is both underwater and volcanic. Also, a fanfic where they get lost in a strange dimension and have to use their combined wits and powers to find their way back home.
One plot twist could be that Sharkboy turns out to be from a future where Lavagirl has become an evil dictator. He travels back in time to stop her from turning bad. This completely flips their relationship dynamic and adds a whole new layer of complexity to the story.
One idea could be exploring their adventures in a new dimension where they have to face a powerful enemy together. Their relationship could deepen as they rely on each other's unique powers.
A character with the power of wind could be added. This character could help Sharkboy and Lavagirl in their adventures by providing fast transportation or creating powerful gusts to fend off enemies. For example, when they are facing a horde of flying creatures, the wind - powered character could blow them away.
The pregnancy could also be a way to bring more unity to their world. Their story of having a child together could inspire others in their world to look past differences. Sharkboy and Lavagirl would become symbols of new beginnings. They would need to teach their child about the importance of using their powers for good, and in the process, they might even discover new aspects of their own powers as they face the challenges of pregnancy and parenthood.
The kiss in the fanfiction also serves as a plot - driving element. It can change the course of their story. For example, it could be the turning point where they decide to face their enemies together more united than ever, or it could be a moment of realization for their true feelings that then leads to further character development.
The kiss is special because it represents the union of their powers in a way. Their relationship is not just about romance, but also about how they complement each other. The kiss can be seen as a physical manifestation of that harmony between them.
One common theme could be the power of their love overcoming challenges. Since they both have unique powers, there might be stories where their love helps them face external threats.