Chapter Text
“Oh, sure! Whatever you say, mama Leo!”
“Stop calling me that, Raph! Is it so bad that I want you guys to be safe?!”
“When you’re breathing down my neck twenty-four seven, yeah! It’s a pain in my shell! Why can’t you just back off?!”
“You know why I can’t do that!”
Not for the first time, and certainly not the last, there is bickering between the A team. For how well they work together, there is always strife. Donnie and Mikey stay blissfully out of the crossfire, neither wanting to be caught in Raph’s anger or Leo’s shepherding.
“Yeah, well, I’m sick and tired of you looking down on us because you’re the oldest! What gives you the right?!” Raph shouts, clenched fists shaking with anger, as Leo scoffs.
“Why would I be looking down on you, Raph?? Honestly! It’s never occurred to you, that maybe it’s out of concern?”
“Oh, like shell it is! You just like rubbing it in my face!”
“You’re unbelievable!”
“I could say the same to you!”
“Uh—guys? Maybe we should move this fighting down into the sewers? We’re gonna catch someone’s attention if we stay up here.” Donnie points this fact out nervously, worried someone may peer into the alleyway at any moment. This does work to break the tension, at least a little. Neither wanted to be caught unawares.
“Whatever,” Raph huffs, turning away from Leo. Without regard for his brothers, he lifts the manhole cover up and hops down. It takes Leo walking over and lifting it, for his other brothers to make it down. He waits until they’re through before gingerly crawling down himself.
The bickering doesn’t pick up, thankfully, as they make their way back home. Raph stomps ahead of them as Leo takes up the rear, holding himself carefully as he watches his brothers for signs of injury. The footbots were one thing, but Rahzar and Fishface were another entirely. He should know.
They all go their separate ways once they hit the lair. Each go through their little routines post-patrol, winding down for bed and such. Quietly, Leo slips away, lucky that Donnie was taking his time in the bathroom. It’s easy to go unnoticed, to slip into the lab, and he’s thankful his brothers are already distracted.
Donnie is just stepping out of the bathroom and into the living room, sans his hand wrappings and letting his bandana hang around his neck, when there is a loud clatter of metal, a distinct yelp, and then nothing. All three brothers freeze, staring between each other with wide eyes.
“I didn’t do it!” Mikey shouts instantly, holding his hands up like he’s being held at gunpoint. As if broken from a spell, Raph is standing, comic book forgotten, with a distinct scowl.
“What the shell was that?”
“It came from my lab,” Donnie points out, dubious. It could be any number of things, but the yelp could only be a certain number of people. He walks towards the doors slowly. “Leo? Are you in my lab?”
“Why would he be in your lab?” Raph asks, but follows along, Mikey not too far behind.
“You got any other ideas?” They all crowd around the door, quiet, trying to listen for any other suspicious noises. Deciding to tear off the band-aid, Donnie throws open the doors. His eyes sweep over the room, trying to find his brother or anything out of place, when—
“Owwww!” A tiny voice cries out from within the lab, and the three brothers freeze.
“What—“
“—was—“
“— that?”
As if on cue, a small mutant turtle, cradling his arm to his chest, walks out from behind Donnie’s desk. The brothers gasp, watching as the teary-eyed child hiccups and cries.
“Papaaaaa!”
That seems to spur them into action, throwing the lab doors shut as to muffle the noise before Splinter finds out. Donnie and Mikey rush over, one coaxing the crying turtle child while the other assesses the situation.
Raph stays back, eyes filled with horror.
“Shh, shh, it’s okay, it’s okay,” Mikey soothes, taking a knee to be closer to Leo’s height. “Do you wanna hug?”
Tiny Leo nods, bottom lip trembling as he shuffles into Mikey’s open arms. Mikey’s first move is to wrap him up tight, wanting to comfort him, but a small ‘ow’ makes him reconsider, drawing away slightly to look down at Leo with a frown.
“Are you hurt, Leo?” The tiny turtle nods. “Where? Can you show me?” He backs up a little to hold out his arm, and Raph seems to start functioning again.
“Leo? You’re saying that’s supposed to be Leo?” He asks dubiously, but his wide-eyed expression tells of just pure disbelief. Mikey gasps.
“Whoa! What happened to your arm?!” At that, Raph’s legs move for him, concern overriding his disbelief completely. He sees it the same time Donnie does, sucking in a sharp breath.
“What the shell?”
“He must have gotten it on patrol,” Donnie realizes aloud, staring down at the angry red line running up Leo’s now smaller arm. It wasn’t deep enough to bleed, but definitely enough to sting. “I didn’t notice it at all. Did you?” He shoots a glance at Mikey and Raph, who share equally shocked expressions, shaking their heads.
“Nah, dude, I was kinda busy watching the two of ‘em fight. I didn’t even notice.”
“That idiot,” Raph hisses, fists clenching. “He hid it, and tried to take care of it himself.”
Having come to that same conclusion, Donnie glances around his desk, trying to figure out how everything went down. He notices the first aid kit on his desk, and his eyes catch on a broken beaker and suddenly, everything makes sense.
“He spilled a failed retromutagen on himself,” he announces, suddenly horrified. “I hadn’t thrown it out yet. Oh god, what have I done?”
“It’s not your fault, Dee,” Mikey reassures, still hugging Leo.
“Yeah, Mikey’s right,” Raph agrees, though his voice is distant, and his eyes are far away. “This is Leo’s fault, for being an idiot.”
“Raph! You can’t call a child an idiot! That’s mean!”
“He’s not actually a child! It’s just an experiment gone wrong. Leo’s probably embarrassed right now that he got caught.”
Mikey’s expression crumpled into a frown, not liking Raph’s accusations. He turns his attention back to the small turtle in his arms, wiping at some of his tears. “Hey, don’t worry about him. He’s just a dumb-dumb. Let’s get that nasty cut cleaned up, okay?” Leo nods, lip still trembling, and he reaches out to grasp Mikey’s hand when the bigger turtle stands. He can’t help but squeal a little, whispering to his two older brothers, “Dudes, he’s so cute!”
Donnie sighs, weary. “Okay. Mikey, you take the first aid kit and help Leo clean up. I’m…going to figure out this mess.” He gestures a hand to the mess of his desk and floor, looking quite tired. Mikey, on the other hand, doesn’t need to be told twice. He grabs the kit, grabs Leo, and leaves his older brothers in the lab to sit in the pit.
There’s blissfully minimal squirming as Mikey gently dabs at the cut. He watches as Leo squirms in his seat, but tries his very best to keep his arm still for Mikey.
“You’re being great for Nurse Mikey, you know that?” He asks and, bless his heart, Leo glows at the praise. The now second-youngest turtle has to bite his lip from squealing at the cuteness, concentrating on spreading a disinfectant cream over the cut. Once done, he wipes the excess on his thighs, smiling. “There we go. All done!”
“Thank you,” Leo says, ever polite. “Can we watch TV now?”
“‘Course, lil dude! What do you wanna watch?”
“Space Heroes!” Leo cheers, bouncing a little. Mikey just laughs a little. He should’ve figured.
“Then, Space Heroes, it is!” He turns on the TV with the remote, switching the channels, when he suddenly gets a lap full of tiny turtle. With wide eyes, he watches as Leo settles into his lap, leaning his carapace against Mikey’s plastron and hugging his knees to his chest.
Holy chalupa, this is nuts.
He can only watch as Leo sings along to the Space Heroes theme song, so small and excited in his lap, and Mikey can’t help but wrap his little older brother in his arms. Unlike how he usually would, Leo leans into it, snuggling Mikey’s arms with his cheek as he continues to watch the show.
Out of the corner of his eye, he notices Raph leave Donnie’s lab, sticking close to the wall as he looks over the pit with dubious eyes. Mikey shoots him a smile.
“Come join us, Raph! Little Leo and I are watching Space Heroes together!” Leo glances over to Raph, staring at his brother with wide blue eyes, not noticing how he tenses.
“Raphie! Come on, it’s the best part!” Leo exclaims excitedly, reaching for the red banded turtle with his hand. With a heated gaze, Raph stares at Leo, only for him to turn and stomp off to his room. Flinching a little as the door is slammed, Leo’s outstretched hand falters and lowers back into his lap with a downcast expression. He looks up at Mikey, confusion swimming in his eyes. “Is Raphie angry at me?” His voice trembles, and Mikey shakes his head quickly to reassure him.
“Nah, lil dude. He’s probably just a lil confused, since you used to be our big brother, now you’re our little brother.” Leo frowns.
“Is that bad?”
“‘Course not! I finally get to be the big bro for once!” He tickles under Leo’s chin, relieved to see the small turtle smile as he giggles.
The two return back to watching the TV until Donnie exits his lab, having finally cleaned up the mess Leo made. He and Mikey share a glance, over the small turtle who’s too engaged in his show to notice.
’We need to tell Master Splinter,’ Says Donnie’s expression.
’I know,’ Replies Mikey’s.
Miley hesitates a moment, watching as Leo leans forward subconsciously to watch his show better.
“Hey, Leo, wanna see Master Splinter?” Leo tears his eyes away from the TV at the mention of Splinter, the expression going from slack-jawed wonder to a bright smile.
“Yeah!” Turning the TV off, Mikey takes Leo with him as they set off for the dojo, Donnie not too far behind.
“Sensei? Uh, we’re home! And we have something to show you!” Donnie cringes at Mikey’s loud voice, but doesn’t say anything about it as he stands beside his brothers. Leo bounces on his toes, and Mikey’s sure if he wasn’t holding his brother’s hand that he’d run up to the screen doors.
“Michelangelo? What is it that you have to—“ Splinter slides open his door, looking as if he was woken from a deep meditation, when he seems to see the little turtle beside them. He stares, speechless, as Leo breaks free from Mikey’s hand and runs full force.
“Papa!” He squeals, running into Splinter’s legs with open arms. Splinter can only stare at the small turtle, placing a tentative hand on his head. His sharp eyes turn on Mikey and Donnie, who both tense.
“Michelangelo, Donatello. Explain.” His tone leaves no room for argument.
“Leo, he— he was trying to get something from my lab, and he knocked over a beaker of my test retromutagen. I knew it was a dud, but I had no idea it would cause— this.” He gestures to Leo, who’s all too content to hug his father, rubbing his scaly cheek against his robes. Mystified by his eldest son’s sudden transformation, he rubs his head like he used to when they were small.
“…Can you fix it?” Donnie stutters the answer, wringing his hands.
“I- I think so. It may take me awhile, but I should be able to figure out how to reverse the transformation. There was some leftover formula that I managed to scoop up, so it should serve as a good base.” Splinter nods, satisfied enough.
“Very well. Then, we shall have Leonardo in this form for the time being.” Though, in truth, it was not a hardship for him. Looking down at this version of Leo, Splinter is brought back to the earlier years, full of shining innocence and wide-eyed curiosity.
And the clinging. Much, much clinging.
Mikey whoops, arms shooting up. “I’m no longer the youngest!!” Donnie gives him a look.
“For now. Once Leo’s back to normal, you’re going to be the baby again.” And just like that, Mikey deflates.
“Aw…”
“Well, it is awfully late for young turtles,” Splinter points out, looking down at Leo pointedly. “Perhaps it is time for bed.”
“Aww,” Leo whines, clinging tighter to Splinter’s robe, “But I’m not tired!”
“Leonardo…”
“No sweat, Master Splinter! I got this!” Mikey swoops in and scoops up Leo, listening to the way he squeals, grinning wider. He rushes the two of them out of the dojo, leaving behind Donnie and Splinter.
“Why do I feel like he’s gonna enjoy this too much?”
“Hm. I believe it will be good for him.”