Disclaimber: I don't own either of these shows, or their adorable sass-master characters!

Rex scowled as he ran after the intruder, it was like chasing a shadow. If you so much as blinked you lost him entirely. He raised his smack hands threateningly and followed the shadow around a corner, only to find him gone.

"Huh?" He blinked in confusion, before realization dawned on him and her threw up his metal covered arms to block the falling shadow as they swung down from the ceiling on a zipline and springboarded off the smack hands, causing Rex to fall on his butt. The shadow landed for a moment, revealing a cape and white slit eyes, before taking off down the hall again. The shadow let out an unsettling, and slightly mocking laugh as they vanished around another corner.

He growled, swinging himself back to his feet and ran after the intruder. The smack hands vanished into his body and he raised a hand to his comm-link. "How did this guy even get in here?" He demanded in irritation, having been chasing the shadow for almost half an hour.

"We have no idea." Came Doctor Holiday's calm reply. "But he hasn't done any damage. According to the security footage, he showed up in a red portal. Oddly enough, despite being the same color, it doesn't share the same sort of energy as Breach's portals." There was concern in her tone, but more so curiosity. "We're not sure if he's a threat yet, but we still want you to detain him, just in case."

He rolled his eyes, catching sight of the shadow again, and speeding up. "Easier said than done Doc, this guy is like a ghost!" He dropped his hand from his ear and brought out his Smack Hands again. The Shadow ran himself into a dead end corridor, and realized it a moment too late. Rex was finally able to get a good look at the intruder he'd been chasing.

He raised both eyebrows in surprise. The shadow, was a kid, a short one with black hair and a domino mask obscuring a good portion of his face. Dressed in red and black with a cape covering most of the outfit from view. The kid was smirking at him with narrowed eyes, Rex could practically see the gears turning in the kid's head. "Who are you?" The EVO-Teen demanded, narrowing his eyes and preparing to attack at a moment's notice.

The Shadow laughed, a creepy, echoing thing that bounced off the walls and around your ears like it was coming from everywhere at once. "Where I'm from, they call me Robin." Without warning the shadow lunged forward, leaping and using Rex's shoulders to flip over the teen with ease and land behind him, ducking to the ground and sweeping the EVO's legs out from under him in one fluid motion. "What do they call you, Man in the Machine?" He quipped, leaning down to look Rex in the eyes.

Rex growled, grabbing for Robin with his Smack Hands, only to miss. Robin had anticipated his attack and ducked to the side with a cocky smirk. With a flick of his wrists Robin had a two winged blade in hand. The EVO narrowed his eyes at the shorter. "Names Rex. Remember it so you can tell people who kicked your butt, comprende, gremlin?" He snapped, throwing a punch. To his growing frustration Robin dodged it again, throwing the winged blade at Rex, it embed itself in the knuckle of his left hand and Rex swore under his breath in spanish.

Robin laughed again, dropping his arms to his side and grinning. "Rex, eh? I'll definitely remember that." He nodded, though seemingly speaking more to himself than anything. He winked at Rex before taking a step back. "Seeya 'round, Terminator." As if on cue, the winged blade in his hand exploded, generating a cloud of smoke and bits of metal. But the time Rex could see again, Robin was gone. The vague echo of a much more genuine laugh and the wrecked bits of Rex's smack hands being the only proof that he'd been there.

Rex stood there for a moment, disoriented, before taking off in the direction of the echo, intent on winning their strange game of Tom and Jerry. Only for Robin to drop down in front of him on a zipline. The raven haired teen was hanging upside down spiderman style inches from Rex's face. "By the way, where's the exit?" Robin asked cheekily, heavily amused by Rex's surprised expression at his sudden reappearance.

"Like I'd tell you." Rex rolled his eyes, getting over his shock and backing up several steps. There was a pause where Robin flipped down from the zipline and stood there with an amused grin, before Rex tackled him to the ground. The two slid down the hall a bit before stopping. "Gotcha!" Rex grinned triumphantly. Robin grasped his wrists and tensed, but Rex barely noticed. "You're coming with me."

Robin smirked. "Forward, aren't you? Most people at least ask me out first." He quipped sarcastically, kicking Rex off of him and flipping into a crouch. "But I suppose social customs are different in other dimensions." He commented offhandedly, before dropping a smoke bomb and attempting to vanish again, only to be grabbed around the torso by one of Rex's smack hands and lifted off the ground. He hissed in surprise. Having thought for sure Rex wouldn't catch on to his cat and mouse game plan just yet.

Rex glowered at Robin. "Do you have any idea how annoying you are?" He asked in a biting tone of voice, though he was blushing in embarrassment from Robin's earlier comment.

Robin scowled, trying to pry himself from Rex's grip. "Oh yeah, I'm told that all the time. What about you, Robot Boy? Get any complaints on your end?" He shot back in an equally biting tone of voice. How could he have let himself get captured? Batman would kill him if he knew he'd been this negligent of his surroundings!

"Che, course I do. Rules this, protocol that." Rex rolled his eyes sarcastically, heading back to the lab where Six, Doctor Holiday, and Caesar were no doubt waiting. "So alternate dimension huh? First time I've heard that one. Probably won't be the last." He kept talking, eyeing Robin suspiciously, knowing he could make a move to escape at any moment.

"Not by a longshot." Robin scoffed. "Not when one of my team's bad guys has been consistently sneaking into your dimension." He figured that this was the good guy organization, if the witty professionally trained teenager was any indication. Normally bad guys weren't so sarcastic. "We dunno why, or who he's meeting, but Klarion is always bad news."

Rex raised an eyebrow. "You've got a lot of explaining to do." He noted, frowning. Just who was this kid? A dimension traveling brat who could probably hold his own against Six and get under just about anyone's skin quicker than Nanites was never good news.

Note!

Might turn this into a series if anyone is interested in the relationship between these two.