A/N: Hello there! My name is Rosalina, and this is what I've spent a good part of my teens doing. I have partnered with my bestie Winter Coma (read her stories, shes amazing) to write this story. To mash up the worlds of RWBY and Ben 10 seems odd, but it just works. There will be some changes to the designs and characters, and in time, this story will have a timeskip. There will also be some original characters, so I really hope you like them! Anyways, please enjoy this first chapter! I'll hopefully update every 1-2 weeks.

Ben Tennyson didn't really know what to say to the girl sitting across from him. Mainly because he had never seen her in his life, nor did he know the relationship between her parents and Grandpa Max. He felt a little betrayed by his grandpa, but maybe an extra passenger in the Rustbucket had been discussed before. He never really paid attention. It didn't look like the girl was paying attention either. She was too busy staring out the window, at the passing traffic, a somewhat distant look in her eyes.

The girl had nice black, neck-length, choppy hair that graduated to dark red at the tips. Not to mention pale skin, an obvious sign that she hadn't been out much. Maybe that's why she'd been forced into this. Maybe folks wanted her to make friends and get a slight tan. Still, Ben didn't really want her on the trip. The road trip was supposed to be a time for Ben and Max to bond, not for some awkward third wheel to join. (Ben hoped he was using that phrase correctly.)

Ben grumbled to himself how ruined his summer was, before his brain offered this ray of light; at least it wasn't Gwen. Little Miss Smarty Pants better remain at her stupid summer university. (Besides, who used summer to do school stuff? Lame.)

"...so, how do you know my grandpa?" Ben attempted to break the silence.

The girl looked away from the window and glanced over at Ben. "Oh? Oh, he's a friend of my dad's. My dad's kinda traveling with my sister for the next few months, and… your grandpa offered to take me for the summer."

"Oh." Ben said. She had an honestly valid reason to be here. "...I don't think I got your name, by the way. I'm Ben."

The girl smiled back, making Ben feel a little more comfortable. "My name's Ruby. Ruby Rose."

"So...where you from?"

"Oh, just some little town in the country. Never really been in a big city before, so, it's kinda overwhelming." She admitted.

"Well, Bellwood is a pretty small city. Don't see why you'd be overwhelmed."

"I suppose I have to start small," Ruby said. "That way I won't be overwhelmed by a bigger version of the experience."

Ben noted how strangely mature this girl seemed. It reminded him of Gwen. But, there was something so innocent and mischievous about her eyes, which… Ben was starting to notice. They were a beautiful silver, nothing like Ben had seen before. Shinier than any quarter or silverware Ben had ever held. He didn't think any human on Earth had eyes like that, and he wondered if that meant there was something inherently special about the girl who had them.

"So, you mind if ask why were you hanging from the tree by your undies?" Ruby teased the boy, making his face red. Ben just looked away and ignored Ruby's giggling.

This was going to be a long road trip.

-
Maybe the shock of Ruby joining the trip wasn't the biggest thing that happened today. Seeing a meteor (or comet, Ben couldn't tell the difference) land on the surface of the Earth right near his location, check it out, and slid into the crater by accident. (Felt like an earthquake, he thought.)

The thing that fell to Earth didn't look like any meteorite or comet, to be honest. Looked like an egg. And that egg opened, and revealed…

"A watch?" Ben raised his eyebrow as he looked at the thing. "What's a watch doing in outer space?"

Suddenly, Ben felt this need to...grab it. He grinned, and reached for it... and suddenly, he had that weird wrist watch attach itself to him.

Everything else? It happened so fast. He was trying to pull it off and, but suddenly he was this terrifying fire monster in a burning forest.

It was totally his fault, by the way, but hey. Accidents happen. Sometimes you may find yourself on fire, able to manipulate and produce flames and just start a forest fire. You'll be fucked, but hey. At least no one knows that you sta-

FWOOSH! Ben was blasted with a face of fire extinguisher. He coughed, backing away. He breathed heavily, while the "flame" on his head reignited. Ruby was standing in front of him, threateningly holding the RV's fire extinguisher. Her eyes weren't showing any signs of fear, something that was a shock to Ben.

"I don't know what you are..." Ruby tried making her high pitched voice sound threatening. "But you're sure as hell responsible for whatever happened tonight."

"H-hey, woah! I didn't mean to! It was an accident!" Ben's new raspy voice defended himself.

Ruby prepared her extinguisher again. "Likely story. Who are you?"

"Ruby, it's me! Ben!"

Ruby's eyes softened a bit. "...what?"

"It's me, Ben! Seriously!"

"...ok, Ben, what happened?"

"Well, when I was walking, this meteor fell from the sky and almost munched me, except that wasn't a meteor or a satellite, but this cool watch thing that jumped up onto my wrist and when I tried to get it off, I suddenly was on fire, only it didn't hurt when I was accidentally starting this mega forest fire. I don't even know what I am!"

"Alien." Ruby said breathlessly. Her eyes were lit in this amazed look, ignoring the hot flames around her. She was too awestruck to care, and honestly, it wasn't the most appropriate reaction for the situation.

Ben just stared at her, a bit concerned. "How do you know it's alien stuff?"

"... Well, it came from the sky." Ruby defended her statement, crossing her arms.

"Ruby!" Grandpa Max ran through the flames, nearly stopping in his tracks when he saw Ben. "Wh-what is..."

"... Hi, Grandpa." Ben said nervously.

"Ben? What happened to you?"

"Well, when I was walking, this meteor…"

"Tell the story around the campfire later, Ben! Major forest fire burning out of control, remember?" Ruby reminded them.

"Right, right," Ben looked around, studying the fire. "So...how are we gonna put this out?"

"Backfire," Max thought out loud. "Start a new fire and let it burn into the old fire. They'll snuff each other out. Think you can do it, Ben?"

Ben smiled. "Shooting flames? I can definitely do that."

When Max saw the forest fire start, he said it was "probably some darn fool out there messing around with something he shouldn't". And he was right. Heck, that could be an explanation for everything that would happen that would happen during the summer! He just didn't expect to see a living, fire manipulating rock monster that was ALSO his grandson. It was a lot for an old man to take in.

"So, that's all that happened?" Grandpa Max asked Ben. Ben was still dealing with the shock of literally being on fire, and nervous tried to tug the watch off. Ruby innocently roasted a marshmallow, somewhat eavesdropping on the conversation.

"Pretty much, yeah." Ben shrugged, chewing on a marshmallow. "I don't even know what this thing is, or why it latched onto me."

"Maybe it's some Green Lantern stuff, like there's a whole legion of those things and you were chosen," Ruby theorized, popping her own toasted marshmallow into her mouth.

"No, it would've spoken." Ben crossed his arms, hoping his comic book smarts would help him. "That, or it would've come off someone who was dying. Plus, I would've been called in by some...council or whatever."

"Can we more focus on the watch, right now?" Max asked, a bit impatient. "I'm going to go to crash site to see if there's anything else present. Ben, don't touch that thing, and Ruby? You're in charge."

"Aw, what?"

Ruby beamed, saluted and nodded happily, before watching Grandpa Max disappear into the tree line, towards the edge of the forest and the landing of the watch… and scooted on over next to Ben.

"Lemme see." She grabbed Ben's wrist, ogling the alien device. It looked like a bulky wristwatch, primarily black and green in color, with an odd dial in the middle (like a watch face) which had a green hourglass shape.

"Pretty cool, right?" Ben bragged, flashing his device.

"Oh, definitely. So, what was it like being an alien?" Ruby inquired.

Ben shrugged. "It freaked me out at first. It was like I was me, but it was also like I was somebody else. Kinda weird, isn't it?"

"Heck yeah it is! So, real talk; how do you make it work?"

Ben nervously looked back down at the watch. "...I actually don't know. Like I said, it was a mistake when I used it the first time."

Ruby fiddled with the dial, but it wouldn't budge. "Maybe it only works for you?"

"Maybe. It is kinda stuck on me…" Ben tired to twist the dial, but nothing happened. "This is just too weird…Look, if I can figure this thing out, maybe I can help people. I mean, really help them. Not just, you know, make things worse!"

Ruby closely examined the device once more, before spying a button on the side. "Maybe press this thing?"

Ben lightly pressed the button, before the dial popped up. A silhouette of the fire guy appeared on the dial. He twisted the watch face a few times, revealing a few more silhouettes...a small one that had headphones on, one that looked like a beetle, a ghost, a velociraptor, a bulky humanoid with two sharp rocks pointing out of its back, a guy in what appeared to be a suit, a lanky humanoid with long arms, a monkey looking creature with four arms and a pterodactyl.

"I count ten aliens." Ruby said. "So… you gonna go another alien? I wanna see what else this thing can do!"

Ben turned the dial to the smaller alien. "This one looks pretty good!" Ben slapped down the dial, before he was enveloped in a bright green light. Ruby had to shield her eyes...the flash was like a green strobe light, bad for her silver eyes...and when it died down, she was face to face with...

"Aww… you're so cute!" Ruby gushed, eyes sparkling and face pinking.

Ben had turned into a small, white alien. This alien had a cube shaped head, a wide mouth and bulging green line like eyes. He had circle-shaped indents on the back of his hands, which were also green. One of his most noticeable features was a square appendage resembling an MP3 player behind his back with a port on it and had what looked like cassette tapes on his lower legs. His legs were also a bit stubby and had three 'toes'. The watch had moved onto his frontal forehead area.

"I'm… not… cute!" Ben's voice was more high pitched, and it sounded like it was coming from a microphone or a voice scrambler.

"No, seriously, you are!" Ruby grinned, petting the boy on the head. "Seriously, I just wanna hug you right now!"

"Stay… back!" Ben hissed as he walked backwards.

"No, come here!" Ruby pounced up, trying to grab the small alien. Ben just responded by… running into the forest. "GET BACK HERE!"

"No! No… hugs!" Ben yelled, a bit fearful. His eyes darted to the forest, and he made gangway right to it.

"Oh, no you don't!" Ruby seemed dead set on cuddling the little guy, as she ran after him.

Ben rushed through the forest, trying to avoid Ruby's devious urge to snuggle the little guy. The sound of her fast feet on the ground made him run even faster, and just made her even faster. Every once in a while, he'd turn around, to see she was still on his track, and coming in hot. She was fast!

"How on earth was she left in charge?" He quipped as he stopped for a few seconds to take a breather, only to have someone grab his shoulder.

"Heya, can I get that hug now?" Ruby teasingly whispered. Shocked, Ben screamed, releasing an intense sonic screech, which caused the ground to shake, as well as a tree to fall over. Ben and Ruby shot each other a look, as Ben awkwardly tried to cover his massive mouth with his tiny hands.

"That… was LOUD." Ruby commented.

"Think Grandpa heard that?" Ben nervously asked.

"Hopefully not, maybe we'll get lucky…" Ruby surmised, before something whirred menacingly behind her. Ruby looked over her shoulder to see one a menacing drone, not of this Earth, floating behind the duo. It had several small limbs armed with lasers and blades attached to its sides.

Ben turned and gasped, before the robot flew at him. Ben and Ruby ducked under the ramming robot, as it kamikazes itself a tree.

"Get out of here! I'll try to lure it out of here!" Ben yelled, pointing Ruby back the direction of the campsite.

"And I'll make sure to go hide somewhere so Max doesn't yell at us!" Ruby said as she ran back to the RV. Ben took off in the opposite direction.

The robot gave him chase, firing a few lasers. Ben skillfully dodged the blasts with his newfound agility (and anime knowledge), and hopped up into a tree branch, and then onto the robot. He took a sharp inhale, before releasing a deadly sonic blast that destroys the robot's head (which he figured was his main computer or tracking thing), and caused the robot to crash into a ditch, with Ben hopping off at last second. He rolled on the ground, and quickly stood up. Ben hoped no one saw that, as the watch started to beep red, and he reverted back to being a human.

Ben smiled as he looked down in the ditch to see the broken robot. "Ha! That'll teach you to mess with me!"

And then he heard whirring behind him. Ben slowly turned to see the same model of that robot, floating menacingly above him. His hair stood on all ends as he turned to face the thing.

"...aw, man." Ben gasped. Those are also some bad last words, He thought.

The robot pointed one of it's many laser beams at Ben, preparing to fire. Ben felt like screaming...Of course, that sheer terror lasted seconds, as the robot was suddenly clunked on the head HARD by a shovel, and that shovel was being wielded by Ruby. The robot began to malfunction and fell to the ground, as Ruby continued to beat it on the head, over and over again.

"No flying hedge trimmer is gonna hurt some member of the Green Lanterns!" She huffed, spitting on the thing.

Ben just stared at her weirdly, but was thankful she was there.

The joy of fighting off an alien from space didn't really last all that long. Max wasn't exactly the happiest when he came back to the Rustbucket, having heard the world's loudest scream.

"I was worried that you might get popular with that thing on your wrist," Max frowned, "That's why I asked you not to fool around with it until we know what the heck it is."

"Look, I'm sorry, Grandpa. But at least Ruby and I figured out how to make it work?" Ben said, with a hint of optimism in his voice.

Ruby motioned to thing. "All you do is press this button. Then, when the faceplate pops up, just twist it until you see the guy you wanna be. Slam it down, and wham! You're one of ten super-cool alien dudes!"

Max sighed and rubbed his temple. "Well, with a device as powerful as that watch clamped on you, my guess is we better help you learn… fast."

Ben and Ruby smiled, and high fived.

-
So, maybe setting the forest on fire wasn't the biggest thing to happen today. Nor was it nearly getting the watch. Not even the drone was the highlight of the day. Rather, it was fighting the giant robot that looked like it was from a standard science fiction manga as a walking chandelier. Ben's body was composed of durable pale green crystals, sporting two crystal shards on his back, sharp blades on his forearms and a sharp point on his head. He also wore a uniform that was black on the right half and green on the left half, with a black patch on his shoulder, where the watch was located.

"Please tell me you're from the Green Lantern Corps," Ruby gushed as she glided her fingers up the crystalized arm. "Please, I need that to be a thing."

"... No, I'm not," Ben said, his voice baritone. There was also a slight crackling sound, like diamonds shifting. Did he always do that when he talked? And more importantly, what did this guy even do?

"Can one of you help me get these civilians out of here?" Max cried out, frustrated. Ben took a look over at the campsite, which was now composed of fire, helpless campers, an overwhelmed park ranger, and the giant alien robot.

"I'll go help Max, you take down ugly," Ruby told him before heading off towards Max.

Ben, unsure of what to do, ran towards the alien. "Hey!" he shouted at it. "Pick on someone your own size!" He pointed his finger at it, which, to his shock, fired a small crystal into the things chest. The robot didn't look seriously harmed by it, but Ben was busy looking at his finger tip, his face saying "how did I do that?"

… and that was when Ben learned how to dodge lasers inside a huge, hulking body. Yay, he thought sarcastically. Trying to hack and slash the thing didn't work, not when the robot could fly into the air, spin its legs, and try and slam into him like a belligerent child's toy. Ben braced himself for pain every time, but honestly? It felt like nothing serious. At least, until the robot caught him.

"Uh-oh," Ben thought as he was captured beneath the robot's feet. "I think I'm in trouble. How can I stop this guy?"

He didn't have time to think, not when the robot picked him up and threw him at a jeep. Crushing the vehicle, Ben slowly sat up, his head aching. "Come on, Tennyson, think," he muttered to himself. The robot loomed over him, its hand outstretched…

"Oh, wait, I'm a living mirror!"

And Ben brought out his two hands, directing the laser away. "What comes around… goes around!" he shouted as he moved the laser towards the robot. "Let's see how you like it, you techno freak!"

As the robot was sliced completely in half, Ben figured he didn't like it at all.

As the morning came, Ruby and Max were packing up the campsite, with Ben nowhere in sight.

"Now, where could that boy have gone?" Max wonder aloud.

"I dunno," Ruby shrugged. "I think I saw him head back into the woods for something."

"Hey guys, check out what I can do!" A voice shouted gleefully. The voice then ran around the campsite at supersonic speeds, tucking away the TV, the fold up chair, anything else they might have left outside. The voice slowed down, revealing itself to be a velociraptor looking alien (with blue and black skin, a visor that went over his eyes when he ran, with athletic-like legs that led into kinetic balls for feet, three spikes on his back and a razor whiptail) which reverted back to ordinary Ben Tennyson.

"He's my new favorite alien," Ruby declared, eyes shining. "He's a speedy dinosaur! You can't beat that."

Ben rolled his eyes, but he couldn't find it in himself to be annoyed. He thought the alien thing was cool too, so he couldn't blame Ruby for her exuberance. Dusting himself off, he said, "I think this is going to be the best summer ever."

"Yeah it is!" Ruby shouted, lifting her hand up for a high five. Ben easily returned it, matching Ruby's smile with his own.

Grandpa Max shook his head and smiled. "Well, I have to agree with you there. By the way, where did you go?"

Ben tried to hide his smirk behind a more easygoing smile. "Just had to take care of a few things before the summer really got rolling."

Somewhere back in Bellwood, two dimwits were hanging from a tree by their underwear, unsure of how they came to be there as it happened quite fast...