Hey y'all, welcome to my new TMNT/Avengers crossover fic Relative Mischief! I came up with the idea after reading a couple of other TMNT/Avengers crossovers. I also remembered that a character from each has the same eye color. So I figured, "Why not make a story that involves this seemingly innocent coincidence?". XD Anyways, I'm not going to spoil anything, so I'll let you guys try and figure out where I'm going with this. Anyways, let's jump right in!

Warnings: Hinted established Frostiron, eventual Raph x T'Challa, some swearing

Disclaimer: I own nothing but the story idea!

"MIKEY!" yelled a voice, the speaker full of rage. From around the corner ran two bipedal humanoid turtles. One was quite short, with light green skin, baby blue eyes, and freckles. He wore mainly wraps on his three-fingered hands, kneepads and elbowpads, a brown belt, brown wraps on his feet, and an orange mask with very short tails. Chasing him was a slightly taller turtle, with kelly green skin and emerald green eyes. He wears almost the same type of outfit as the smaller turtle, but with several differences, most notably the fact that instead of orange his mask was bright red with longer tails that were frayed on the ends. He also has a lightning bolt shaped chip in his plastron and several scratches on his shell, showing he often got into fights.

"I'M GOING TO KILL YOU MICHELANGELO!" the taller turtle yelled. "I'm sorry Raph! It was just a prank bro!" Mikey shouted, screaming as he ran from the older turtle. This lasted for a bit until both Raph and Mikey were grabbed by humanoid mutant rat with black, brown, and white fur and wearing a red kimono. "What is going on here!?" he demanded, though he didn't yell. "Mikey snuck cockroaches into my room!" Raph yelled, growling. The rat looked at Mikey. "Is this true Michelangelo?" he asked, his voice calm.

"It was just a prank Master Splinter!" Mikey said, pouting. "The first couple of times were pranks Mikey, but you're starting to get into bullying territory now..." said another turtle nearby. This one was taller than Raph and Mikey, almost as tall as Splinter. He had tea green skin and reddish brown eyes, along with a gap in his teeth. The only difference to his outfit was that his mask was purple with tails as long as the ones on Raph's mask. "But Donnie..." Mikey whined, crossing his arms. "I'm sorry Mikey, but it's true... plus with Raph's fear it won't end well it you keep it up..." Donnie said, turning to continue tinkering with the small machine he had on the table.

"Michelangelo, apologize." Splinter said calmly but sternly. "Fine... Sorry Raph..." Mikey said quietly. "Yeah, well don't do it again..." said Raph, managing to get out of Splinter's grip and leave the room, pushing past a fourth turtle. This turtle had emerald green skin and sapphire blue eyes that matched the mask he was wearing. "What's his problem?" he asked, turning to the others after Raph left. Mikey looked at the ground and shuffled his feet, which was answer enough for the newcomer. "Mikey..." said the turtle, frowning and crossing his arms. "I didn't mean for it to get this out of hand Leo..." the youngest turtle said, sighing then looking up when the oldest turtle gently placed a hand on his shoulder.

"I know Mikey... honestly, I think you helped Raph get over his fear a little bit..." Leo said, grinning. "Really!?" Mikey asked, getting starry-eyed. "Yeah... but it might be best to wait a while before doing it again..." Leo stated, laughing when Mikey pouted.

Raph, meanwhile, was stomping through the sewers, trying to get his anger under control. Mikey knew how much he hated cockroaches; how much they terrified him. Still deep down he felt as if Mikey was inadvertently trying to help him conquer his fear. He would've appreciated the thought, but at the moment was too angry to care. He decided he would go to his secret spot, one that even Splinter didn't know about. He discovered it a while back and would go there whenever he needed or wanted time to himself.

Making his way through the sewers, he soon found the crevice that led to his secret spot and squeezed through, thankful nobody had filled it in. It was quite a ways away from the lair, and he liked it that way. He felt around and hit a switch, which turned on the single lightbulb in the room. It looked like it was from some underground bunker, and was filled with what looked like rusted and broken bits of robots and others machines. A hole in the roof revealed that it was in fact a dumping ground for supposed projects, as everytime Raph entered he would find a new pile of mechanical scraps under the chute, and this time was no different.

Raph walked over and begins sorting through the scraps. He wasn't sure why, but recently he had developed a hobby of tinkering with the scraps he found. It started when he first found the room, and it came to him almost like a second nature, a habit he hadn't known he had. Normally tinkering was Donnie's area of expertise, but after a couple of days of coming to the room he found that it just felt so natural to try and make things with the scraps and broken tools he had. He even managed to create a small working spider-like robot from the scraps he had, which he called Achilles. Said robot scuttled up to him like always, chirping.

"Hey Achilles..." he said, shifting through the pile and looking over the scraps. The robot chirped again. "Huh? Naw, just had to get away from the lair a bit..." he said, talking to the robot as if it were another biological being. He didn't dare take Achilles back to lair for fear that Donnie might take him apart, and he couldn't stand the thought of that happening. Soon he found what looked like a very complicated computer chip, surprisingly still intact. "Well would you look at that... maybe I can use this to build you a friend so you won't be lonely when I leave..." Raph said, grinning at the small robot, who chirped happily. He laughed and wondered if there were anymore useful things he could us to make said companion. He didn't care where the parts came from; all he knew was that they came from the chute above his secret room.

If he had bothered reading the slightly rusted signed on part of the chute, he would have seen the words "Property of Stark Industries".

WHEW! That took almost an hour to write! How do you guys like it so far? I have a feeling this might be quite a long story, and I'm totally looking forward to it!

Until next time, Icy it out!