I'm going to make a fanfic based on Ben 10 and Teen Titans this time! And yes, I like making crossover fanfics...I had trouble deciding what I should crossover Ben 10 with though...then it occurred to me that maybe I should cross Ben 10 with Teen Titans. It seemed like a good idea.

And yes, this fanfic will take place in Jump City. I think I'll probably feature the Null Void as well, though. You know, where the plumbers send alien criminals? It's nightmarish!

Chapter 1: Another Omnitrix

Inside a spaceship, Albedo was attempting to create his own Omnitrix. He insisted on attempting to obtain its power for himself, even though Azmuth insisted that it was designed for peace, not for war. Unfortunately, neither he nor Vilgax had gotten that message.

That, and he wasn't too fond of his former master. He didn't seem to treat his apprentices too well.

"A few more modifications...I've done it!" exclaimed Albedo.

He now had an Omnitrix of his very own. He could use it for whatever he wished.

However, he hadn't really thought about what to do with it. He thought about conquering the galaxy...but that seemed cliched. He felt like he could do something that was more creative with the Omnitrix.

He of course wasn't going to use his forged Omnitrix to do anything heroic. He wasn't like Ben Tennyson. He was such a goody two-shoes. Personally he was rather baffled that he could defeat someone like Vilgax even though he was just a kid. Vilgax had killed some of the galaxy's best plumbers...as well as his killer robots, which he was in no short supply of.

Well, he could decide later. For now, all that was left to do was add some DNA samples to the Omnitrix. The Omnitrix wasn't much good if you couldn't use it to shapeshift into aliens.

Fortunately, he had obtained quite a few DNA samples for this purpose. Naturally, one of them was a Galvan...much like the creator of the Omnitrix himself.

However, just as he was finished placing DNA samples inside his duplicate Omnitrix, he suddenly heard the sound of a laser going off.

A few seconds later, his ship began to shake.

He wondered what was going on, and decided to look out the window.

He discovered that it was Vilgax, and knew at once what he was attacking his ship for.

"How did he figure out about the Omnitrix I was building so quickly?" asked Albedo.

To think that he had just finished forging an Omnitrix. His luck was simply terrible.

He then noticed that there was a miniature robot on the ceiling.

Albedo sighed. It looked as if he had been spying on him the whole time-waiting for the opportunity to seize Albedo's forged Omnitrix for himself.

He fired a laser at the robot and destroyed it, then began to think of an escape plan.

Fortunately, there was an escape pod nearby.

He grabbed the Omnitrix and then ran towards it.

However, he lost his balance and tripped, causing the Omnitrix to fall into the escape pod.

Vilgax fired a laser at his ship once again, and the escape pod descended from his ship.

"No!" exclaimed Albedo.

Shortly afterwards, Vilgax's robots boarded the ship.

Sweat began to protrude down Albedo's face. He was starting to wonder if he should have set up some defense systems on his ship. He was wanted by the plumbers, after all.

Vilgax himself was there to confront Albedo.

"Give me your Omnitrix!" exclaimed Vilgax.

"I don't have it..." said Albedo.

"What?!" shouted the squid-faced alien.

"I DID have it...but I lost it..." stated Azmuth's former assistant.

Vilgax grabbed him by the neck, causing his eyes to widen in horror.

"Where is it?" asked Vilgax.

"I set the coordinates...to the nearest planet..." stated Albedo.

As it turned out, that planet happened to be Earth.

Vilgax let go of Albedo's neck, who promptly gasped for air.

It looked as if he would be paying that particular planet a visit...again.

The Chimera Sui Generis thought about his next course of action. Should he chase after it? He wasn't sure where exactly on the planet it was. He was tempted to destroy the planet to spite his enemy Ben...but with a duplicate Omnitrix on the planet that would mean that it would go to waste. He would have to put destroying Earth on hold, satisfying as it would be to watch it explode.

It then occurred to him that if any of Ben's friends and family got their hands on it, he could be in a lot of trouble. Ben Tennyson had caused him enough trouble as it was.

Vilgax could only imagine if another family member of his got their hands on the Omnitrix as well. Max Tennyson in particular could throw his plans into massive chaos, especially since he was a plumber that had hold his own against him even WITHOUT such a device.

It would be best if he found it before anyone else did. Besides, it would assist him greatly in conquering the universe. He had already conquered many planets, but it always seemed like there were plenty more.

So, he departed from Albedo's spaceship and began to head to Earth.

Of course, this wouldn't be the first time he paid that particular planet a visit. It happened to be the home planet of his archenemy. He had considered destroying it and take out his enemy in one fell swoop, but the Plumbers had set a force field around it so it wouldn't be easy.

Albedo let out a sigh as Vilgax departed. It was very likely that considering the many robots that he had at his disposal that he would find it before he did.

It looked like he would have to build another Omnitrix from scratch.

Well, he might as well get started.

At the Teen Titans Tower...

In the middle of the night, after spending a day fighting evil as normal, the Teen Titans were enjoying a well-deserved break. It had been hard work fighting off all the members of their rogues gallery, but they had managed to pull it off in the end.

"Good work titans. It seems that the city is safe...for now." said Robin.

"Why does it keep being invaded?" asked Cyborg. It seemed like Jump City was some sort of magnet for criminal activity. Each supervillain was crazier than the next.

Beast Boy shrugged.

Suddenly, they noticed a strange comet.

"What was that?" asked Raven.

"Maybe we can make a wish?" inquired Beast Boy.

"Something was off about it..." said Cyborg, scratching his partly metal head.

"I sure hope that this isn't a sign of an alien invasion..." said Robin. As Cyborg had said, there was something unnatural about that comet. For one thing, it was red.

He wondered why it landed so close to their tower. Was it a coincidence...or was it something bad?

"Does...anyone want to check it out?" asked Raven.

Starfire nodded.

"Starfire? You'll investigate the comet?" inquired Robin.

"Well, if it's an alien invasion, I'd probably know to handle it the best." noted Starfire. She had met many aliens in her lifetime.

"You've got a point." nodded the boy. Sometimes he forgot that Starfire WAS an alien.

Starfire went outside to investigate it.

However, there was no sign of a spacecraft...just what seemed to be some sort of escape pod.

The alien princess wondered if something horrible had happened. Had there been an intergalactic war? Some aliens never seemed to get along.

Perhaps an alien had come seeking their help? She wouldn't put it past them.

She went to investigate.

However, Starfire didn't find anything out of the ordinary...except for what seemed to be a watch.

It didn't look like any watch that she had ever seen though.

She went closer to investigate...and ended up stepping on it by accident.

The Omnitrix ended up fusing to her leg.

Starfire wondered what was going on.

She tried to shake it off, but could not.

Not even her super strength could remove it.

The alien scratched her head.

She sure hoped that the device wasn't dangerous. There was alien technology that was fully capable of destroying a planet. She dreaded the thought of one of it firing on her home planet.

It then occurred to her that perhaps Robin could remove it. He did have his share of gadgets after all. Although, unlike his teammates, he did not possess any special superpowers.

However, Starfire couldn't help but wonder what the device did.

She decided to turn the knob on her new leg bracelet

A projection of a Vulpimancer appeared.

"A Vulpimancer? I heard that they live on a planet that's virtually uninhabitable." noted Starfire. The rest of the galaxy used it as a dumping ground. It was surprising that life could survive on that particular planet.

Well, she might as well give her bracelet a test run.

She decided to press the button on the Omnitrix.

Shortly afterwards, she transformed into a Vulpimancer.

She scratched her head curiously.

Apparently, this strange anklet she had allowed her to shapeshift...similar to Beast Boy.

However, it seemed that instead of transforming into animals, her new leg bracelet allowed her to transform into aliens.

Ironically, she was already an alien herself.

However, at that very moment, Beast Boy showed up.

"Starfire? You there? Robin was worried after you didn't come back so he decided to check on you..." stated Beast Boy.

Starfire thought it was rather sweet that Robin wanted to check on her.

However, it then occurred to her that Beast Boy probably wouldn't recognize her in her new form.

Was...there a way to change back?

She sure hoped so. Starfire imagined that there was a way.

"Wait...you're not Starfire!" exclaimed Beast Boy.

The green-skinned boy gasped.

"Aah! Starfire got eaten by a space alien! Some sort of space dog!" shouted the boy.

Beast Boy believed this to be true...even though there were no signs of a struggle or any remnants of Starfire's outfit.

Angered by what he thought the extraterrestrial animal had done, he transformed into a bear.

"You're going to pay!" exclaimed Beast Boy.

Starfire realized that Beast Boy didn't recognize her in this state.

Of course, she did feel like a different person when she was a different alien. She still had her brain though, apparently. The Tamaran didn't feel too animalistic in her current state.

Unfortunately, she did not know how to transform back, so it looked like she couldn't communicate with Beast Boy and try to explain that she wasn't a dangerous space alien.

On the lighter side of things, it seemed that her new alien dog form was fully capable of defending itself. Though it wasn't capable of sight, it had very good hearing and an equally good sense of smell.

It also packed a mean bite.

"Ow!" exclaimed Beast Boy.

Beast Boy tried attacking Starfire, but she was too quick for him.

"This space canine is fast!" exclaimed Beast Boy.

He decided to shapeshift into a tiger. Maybe a different animal will help him take down this extraterrestrial beast.

He then scratched Starfire with his claws.

Fortunately for Starfire, it seemed that Vulpimancers were a very resilient species. Being scratched by Beast Boy didn't hurt too much.

Suddenly, Starfire began to hear a beeping noise.

Was there some sort of timer for the Omnitrix?

A few seconds later, Starfire turned back to normal.

"Starfire?" questioned Beast Boy.

"That was an out-of-body experience..." said Starfire.

"Wait...that alien was you?" inquired the green boy.

The space princess nodded.

"I'm sorry, Starfire! I thought you were some sort of mutt from outer space! Well, you are from outer space..." noted Beast Boy.

"Yeah...I can't seem to communicate when I transform into one of those." acknowledged Starfire. Perhaps she should focus on shapeshifting into different forms for the time being so she could continue communicating with her teammates.

At least she knew now that it was only a temporary transformation and she didn't have to worry about being trapped in the wrong body. It would really stink if she was trapped in the form of an alien unfamiliar to her.

"What's that on your leg?" inquired the boy.

"I wish I knew..." answered Starfire. "However, it lets me shapeshift into different aliens..."

"You can do that? You are so lucky!" exclaimed Beast Boy.

"Can't you shapeshift?" asked the princess.

"Not into space aliens!" exclaimed the green-skinned boy.

Starfire and Beast Boy went back inside the tower.

"Why do you have a bracelet on your leg?" asked Raven. There was something off about it.

"Doesn't look like any sort of technology that I've ever seen..." stated Cyborg. Considering who he was, that was saying a lot.

Starfire went to Robin to discuss her new bracelet.

Robin decided to investigate the Omnitrix.

"This is very strange...the device seems to have attached itself to your DNA." said Robin.

"It has?" asked Starfire.

Robin nodded.

Something told her that it was going to be difficult to remove.

The bracelet kept getting stranger and stranger.

But at least it wasn't dangerous.

However, something told him that the device could be dangerous in the wrong hands. If one could shapeshift into a variety of different, powerful aliens, they could cause a lot of destruction.

Perhaps it would be best if they kept an eye on Starfire from now on.

Meanwhile...

Once again, Ben was feeling rather excited. It was summer vacation, again!

He in particular was looking forward to being with his Grandpa Max. He happened to be a plumber...but it didn't involve toilets.

Of course, there was his annoying cousin Gwen...but he could put up with her. Apparently she didn't think that he was mature. In his defense, he now had a B average at school instead of a C average.

Something told him that he would be called upon to fight evil once more. Things had been rather quiet while he was at school.

This time, they were going to spend the summer at Jump City.

It seemed like a good place to be.

However, he also heard that there were having some issues with criminals that kept looting the city. Where were the police when you needed them?

Well, if he ever encountered them, he knew what to do. He would use the Omnitrix and clobber them.

Sure enough, he could see a criminal right outside the trailer.

He was stealing a lollipop from a baby.

The baby started to cry.

"Seriously?" said Ben.

For the time being, he decided to transform into Fourarms.

He picked up the criminal and gave him a wedgie.

Afterwards, Ben returned the lollipop to the infant, who stopped crying.

He smiled with satisfaction...but he couldn't help but shake the feeling that there were more dangerous criminals in this city than a petty thief.

For now, he changed back to his human form. He didn't get the Omnitrix for free...it had a recharge time.

Thus, he decided he would try to put it to good use.

He decided to check the newspaper to see if he could learn more about this city.

Apparently, there was a team of superheroes protecting it. They had saved the city so many times.

"There is? I'm starting to wonder if I'm going to need to lift a finger..." said Ben. He sure hoped that there was room in this city for another superhero.

Was his summer vacation going to be boring? His last one had been rather exciting, what with the many supervillains that he kept fighting.

He hoped that it wouldn't be boring.

Well, it was doubtful that they could be everywhere in the city at once.

For now, he was going to eat some chili dogs.

I figured I would be a bit creative and have the Omnitrix latch onto Starfire's leg instead of her arm. I could have given Robin the Omnitrix but Starfire was more similar to Ben in personality. Besides, there has been fan art featuring Ben transforming into Starfire on account on her being an alien. And of course, I figured it would be appropriate for Starfire to obtain one since she's an extraterrestrial.

Let me know if there are any villains from either shows that you want to feature. I'll try to be creative though.

And yes, Vilgax will be a villain in this fanfic. If there's any Ben 10 villain I should include, it's him.