Today, (Y/N) asked their brothers something that shocked them all...

"What's a birthday?"

"You-You don't know what a birthday is?!" Mikey exclaimed, slightly freaking out. They simply shook their head.

"Well, I suppose it makes sense," Donnie said as (Y/N) tilted their head to the side in confusion, "They were abandoned at a very young age, so it only makes sense as they were not raised properly and are unaware of most traditions families share with their young."

"Don't worry, (N/N)!" Leo exclaimed, picking them up and placing them on his shoulders, "We're gonna throw you the best birthday party anyone's ever seen!"

That...That ended in chaos.

Explosions were going on, Leo and Mikey were running around trying not to die, and Raph had you over his shoulder running away from a killer robot.

"April still hasn't gotten through the 'Happy Birthday' song yet, guys!" Donnie called out. "There's a song?!" (Y/N) exclaimed. "April still hasn't gotten through the 'Happy Birthday' song?" Raph questioned. "Am I on speaker?!" April yelled/asked into the phone.

"Or cake, actually," Donnie added on. "Pff- Or cake?" Leo scoffed, jokingly.

"Albearto's is the pizza place, right?" Raph questioned, "Perfect place for a B-day Kid like (Y/N)! We'll be right there!"

"Hey, if you guys are in the middle of something—" April couldn't even finish, as the turtle brothers and (Y/N) burst in through the door, their weapons in hand. Raph yelled out, "Fixers in the house, swooping in to save the day!"

"That was fast," April said, "Actually, I just needed Donnie." "Oh, we know," Raph assured, "We just came here for the free pizza." "And for (Y/N) to see what's so amazing about a birthday!" Mikey added on, "Go on, (Y/N), go out there and play with the other kids!"

(Y/N) giggled, nodding as they ran out. They made sure the top of their staff wasn't pointed so they wouldn't hurt anyone as they ran around. They giggled as they played a few games, and even played with other kids, forming small friendships.

(Y/N) was about to win one of the games, before hearing something from the stage. "Bon giorno, kiddies!" the animatronic bear called out. The child ran into the crowd around the stage, curious as to what was going on.

"Is he gonna break again?" one of the kids asked. "Not on my watch! Again," April said while Donnie was by her side, holding a sort of remote control.

"Hold onto your birthday hats, kiddies!" he yelled, before hard rock music started playing.

"And now for a guitar solo, you're welcome!" (Y/N) barely managed to hear over he music, which was just a bit too loud for (Y/N)'s liking, so they went off to play a game or something.

Soon, someone caught their eye. They were unsure why; She looked like just an ordinary teenage girl. Long, curly brown hair in a ponytail, dark blue eyes staring down at her phone, a dark purple hoodie with a plain white t-shirt underneath, some sports pants, and some dark blue tennis shoes tennis shoes.

Maybe it was the foldable fans in her pocket? Maybe it was because she paid little to no attention to the music blasting? Was that what brought their attention? Or perhaps it was the necklace with a rather large locket  about the size of a finger on it around her neck?

It seems as though (Y/N) caught the attention of the teen female as well, as she looked up from her phone, her eyes immediately drawn to the staff the child wielded.

She smiled as she looked around, putting her phone in her pocket as she slowly started to approach the small one. She made a shushing noise as she placed a finger over her mouth, signaling for the young one to keep a secret. She took the necklace from around her neck and placed it around the small one's neck. "I want you to keep this with you. Don't look at what's inside the locket. Trust me. Just enjoy the locket itself."

"Happy Birthday, little one," she said, standing up and ruffling their hair before making her way out of the pizzeria.

(Y/N) stared for a moment, before hearing strange noises from the stage. "No, no, no, no!" they heard Donnie yell, "He should not be glitching! He should be rocking and/or rolling!"

They looked over to see Albearto spazzing our like crazy. In panic, they grabbed their staff, ready to defend if needed.

Soon, there was an explosion, covering everyone in ash and such. "Ok! So that happened!" April yelled, trying to break any tension, "But! We can still sing happy birthday without him! Happy birthday—"

There was soon a groan coming from Albearto. There were screams and whimpers, as (Y/N)'s grip on their staff tightened as they backed up.

"Time to pump this party up," Albearto said, standing up, "Let's play!" He started charging at the children. (Y/N) was having none of this, and turned the tip of their wing into a blade. They aimed it at Albearto, before throwing it, causing it to land in his shoulder.

Albearto twitched, before turning his head slowly at (Y/N). "That wasn't very nice, kiddie..." he said, taking the staff from his back. Then, he aimed it at (Y/N), before throwing it. They gasped, jumping out of the way, making the staff nearly hit the birthday boy.

(Y/N) ran over, trying to pry the staff from its place. They felt Albearto slowly approach them from behind. They turned around and screamed, when April jumped in the way wit a tray, "Play nice, Albearto!" She swung the tray, causing Alberto's hands to fly off.

(Y/N) and the boy clung to April's legs. "Run, kids!" she yelled, making the two of you run off. You managed to grab your staff on your way over.

(Y/N) and little Timmy ducked under a table for safety. "Who wants to play a little game of follow the leader to safety?" April asked, holding the tray to her chest.

The kids didn't hesitate to follow April to the nearest exit. However, (Y/N) hesitated. "C'mon, (Y/N)!" April called out as the last kid, who was texting away on his phone as if his life wasn't in danger, walked out the door, "You can come back to Albearto's when you're done fleeing for your life!"

They hesitated for a moment, before shaking their head, "No! I wanna help!"

Before April could deny, the two watched Raph punched Albearto. "Don't worry, (Y/N)," Raph said, "He might have them crazy, but we've got the numbers! You and April go ahead and bounce if you need to."

"Don't leave, I haven't handed out the party invitations yet!" Albearto exclaimed, sending wires over to the other two animatronics come to life. They jumped up, getting into a battle position.

"Uh, he's bringing the robots to life!" Donnie pointed out. However, Raph didn't lose his confidence, "No sweat, we've still got this!"

It wasn't until he brought the things from Whack-A-Mole (can't remember if that was the game, but I'm going with it—) to life as well. "Eheh, you didn't have any plans for today, did ya?" Raph nervously asked.

"Oh, I'm staying," April said confidently, "I am the Party Captain, and I am saving Timmy's party from disaster!" There was a yell from the Whack-A-Mole game, as Timmy was surrounded by the moles. "Right after I save Timmy," April said, before charging forward.

It didn't take long for little (Y/N) to get lost in the chaos, earning some cuts all over their body. They managed to crawl out of sight and heal some of their cuts, when Albearto snuck up on them from behind.

"Oh, like heck I'm gonna let you ruin (Y/N)'s first birthday celebration!" Leo yelled, blocking Alberto's attack. However, it didn't take long for Albearto to knock Leo into a table.

The older brother in red let out a battle cry as he charged towards Albearto, attempting and failing to defeat him. "If I can't have a birthday party, nobody can!"

That's what gave (Y/N) an idea. As Mikey and Donnie held Albearto off, (Y/N) managed to find a birthday cake in the back of the pizzeria.

"You can share my birthday!" they called out, running out of the room with the cake in hand, an innocent smile on their face.

Albearto let out a loud yell, until he realized what the young one had said, "Wait, really? A birthday party? For meesy-weesy?" "Yeah!" the young one exclaimed, walking over.

Donnie picked them up with one arm, holding the cake in his other arm, "Yes, Albearto, today's the day you were born! Through a total accident that's clearly nobody's fault."

"A birthday cakey-wakey?" Albearto questioned, "For meesy-weesy?" "And a song!" (Y/N) exclaimed, throwing their arms in the air.

"Happy birthday to you," (Y/N) and Donnie started singing, when Raph, Leo, and Mikey, joined in, "Happy birthday to—"

As they sang and Albearto started sniffling, April jumped in and started beating the crap out of Albearto. Cake started flying everywhere, and Donnie quickly used his arm to cover (Y/N)'s eyes so they wouldn't have to see their friend beat a robotic head to "death".

April took a few deep breathes, before pointing at the guys and (Y/N), yelling, "Sing with me, guys! I am finishing this party! Happy birthday- Finish the song!"

"Dear..."
"Kid..."
"Squirt."
"...Albearto?"
"(Y/N)....?"
"Uhm..."
"Happy birthday to you."

Without warning, the building started crumbling, and eventually collapsed. "Well...Later, April!" Leo called out. "Have fun cleanin' up!" Raph called out. "We've gotta take (Y/N) home, it's getting pretty late!" Mikey exclaimed as he and his brothers rushed back to the lair.

~^~

(Y/N) yawned as Raph tucked them into bed, and they started snoring as they slept away.

"I just realized, we weren't able to give (Y/N) a proper birthday party!" Mikey whisper-yelled.

"Worry not," Donnie said, patting his younger brother's shoulder, "We can still redeem ourselves."

~^~

The young one rubbed their eyes as they looked around. They yelped and jumped a bit in shock as they saw their brothers around them with wide grins.

"Wha...?" "No time for questioning, (N/N)!" Leo exclaimed as Raph picked them up, "We've got something to show you!"

He carried (Y/N) to the kitchen, where Splinter, April, a large cake and a pile of presents was waiting for them. "Happy birthday, (Y/N)!" they all exclaimed. The little one squealed, hugging them all, "I love it! Thank you!"

1843 words
eyyY, iS MaH B-dAy! So I thought, "Why not do a birthday special?!" aNd WhAT A cOincIDeNcE tHaT ThIs ePisoDe iS 'War and Pizza'! yeET—
Also, the majority of people voted for me to put in an OC, so I did that! Hope you enjoyed the chapter, and I hope adding in the OC wasn't a mistake—