Well, it could be really wild. Maybe Steven could use his gem powers to try and stop Zim's crazy plans for world domination. Zim, on the other hand, would probably be super confused by Steven's powers and the whole concept of gems.
In a crossover fanfiction, the settings of both shows could blend. The strange alien landscapes from Invader Zim could intersect with the colorful and magical places in Steven Universe. Zim's robot, GIR, might get into some wacky adventures with Steven's friends. And perhaps the Diamonds from Steven Universe would view Zim as a new threat or an interesting oddity, which would add a whole new layer of drama and humor to the story.
A Steven Universe and Invader Zim crossover fanfiction might involve the Crystal Gems and Dib teaming up. Dib would be fascinated by the Gems' abilities and technology, while the Gems would see Dib as an ally in the fight against Zim's evil schemes. Steven could also try to befriend Zim, thinking he could change him, which would lead to some really interesting and comical situations.
I think Steven and Zim would be the most interesting pair. Steven's kind - hearted and positive nature contrasted with Zim's evil and self - centered personality would create a lot of comical and tense moments.
One possible plot could be that Zim and Dib from 'Invader Zim' somehow end up in the 'Futurama' universe. Zim might see the advanced technology in Futurama as a new opportunity to take over a planet. He could mistake Planet Express for a major power center and try to infiltrate it. Dib, on the other hand, would be excited to explore this new world and might team up with Fry, Leela, and Bender to stop Zim's new evil plan.
A Markiplier and Steven Universe crossover fanfiction could be really interesting. Maybe Markiplier's character could end up in the world of Steven Universe. He could interact with the Crystal Gems, and his comedic and often chaotic personality would create some really fun and unexpected situations. For example, he might try to help Steven with his gem powers in a very unorthodox way that would make everyone laugh.
It could be really cool. Imagine Steven's gem powers interacting with the Transformers' technology. Maybe the Crystal Gems could help the Autobots in some way, like using their powers to repair damaged parts. Or the Transformers could introduce new ways of using energy to the Gems.
It could be really interesting. Maybe the gems from Steven Universe end up in the spooky world of FNAF. They could use their powers to fight off the animatronics. For example, Garnet's strength could be used to hold the animatronics back while Pearl uses her spear to disable them.
There could be all sorts of fun scenarios! Maybe the Doctor lands in Invader Zim's universe and has to help him deal with some crazy alien threats.
In such a crossover fanfiction, Gir could get into all sorts of trouble in Gravity Falls. He might mistake a Wendigo for a new type of snack. Meanwhile, Mabel could try to befriend Zim, thinking he's just a really odd - looking new friend. The story could involve a race against time as Zim's evil plans start to affect the delicate balance of Gravity Falls, and the local characters have to team up with Dib to stop him.
A possible crossover could involve the magic system of Harry Potter being combined with the Gem technology in Steven Universe. For example, Hermione could study how the Gems' powers work and try to find a scientific explanation for it. On the other hand, Pearl could be fascinated by the complex spells in the wizarding world. And perhaps Dumbledore and Garnet could have a deep conversation about leadership and protecting their respective worlds.
A possible Undertale and Steven Universe crossover fanfic could be really interesting. It might involve characters from both universes meeting in a strange new world. For example, Steven could end up in the Underground from Undertale. He would probably try to use his powers of peace and love to resolve conflicts there, like how he does in his own show. Maybe he'd meet Sans and Papyrus, and there could be some really funny interactions. Sans with his laid - back attitude and Steven's positive energy would make for a great comical duo.
The clash of different aesthetics. Jhonen Vasquez has a very distinct style in both JTHM and Invader Zim. When you cross them over, you get a really unique visual and narrative blend.