In a 'Naruto Monsters vs Aliens' fanfic, perhaps the aliens are trying to enslave the people of the Naruto world. The monsters, which were once feared by the villagers, now become unexpected allies. Naruto, with his belief in friendship and understanding, tries to bridge the gap between the two groups. He might train with the monsters to learn new combat techniques and in turn, teach them about the importance of unity. Together, they could fight against the aliens' mind - control devices and save the world.
In a fanfiction, the aliens could capture Naruto and try to study his unique abilities. The monsters then decide to rescue him because they realize his powers could be the key to defeating the aliens once and for all. The story could involve a lot of action as the monsters infiltrate the alien base to save Naruto.
In addition to the regular Naruto characters, some of the more powerful monsters could be main characters too. For instance, a giant dragon - like monster that has the power of flight and can breathe ice. It could be a reluctant ally at first but then grow to respect Naruto and his friends. And among the aliens, there could be a leader - type character who is extremely intelligent and has unique powers that pose a great threat to the Naruto world.
One idea could be a story where the monsters and aliens have to team up against an even greater threat from another dimension. Maybe a powerful interdimensional being that wants to conquer both Earth and the alien planets.
In Naruto Monsters vs Aliens fanfiction, it's hard to say who would win. Naruto's monsters have unique ninja abilities like chakra control and powerful jutsus. However, aliens might have advanced technology and strange powers. If the aliens' technology can disrupt chakra, they could have an advantage. But Naruto monsters are used to fighting in their own world's crazy battles.
The Missing Link is also quite popular. His brash and confident personality can add a lot of humor and action to a fanfic. He could be on a quest for glory or trying to prove himself to the other monsters.
The plot involves a group of monsters coming together to fight against aliens. Susan becomes Ginormica and teams up with the likes of B.O.B, Dr. Cockroach, and The Missing Link to save the world from the alien threat.
One plot idea could be that aliens invade the Naruto world seeking a powerful energy source, which is actually the chakra. The Naruto monsters then team up to defend their world. Another could be a group of Naruto monsters getting accidentally transported to an alien planet and having to fight their way back home. They could learn new techniques from the aliens they encounter during their journey.
The relationship might start with curiosity. The OC could be curious about Susan's abilities and Susan could be interested in the OC's origin. As they start to communicate and work together on small tasks, like helping the monsters train for a potential threat, their relationship gradually deepens.
A scary story might involve a particular monster in Monsters vs Aliens. For example, the Insectosaurus. When she gets out of control and starts rampaging through the city. Her huge size and the destruction she can cause is quite scary. Imagine a giant bug-like creature smashing through skyscrapers and chasing people.