Flufftober 2026 theme: Signature Move
Baby Tails in Underground AU
By: KrissieDeathy
This is written using Tumblr’s Fluffotober 2026 prompt for Day 3. You can find the prompt list here: https://www.tumblr.com/flufftober/820930227266027520/hello-and-welcome-to-our-sixth-annual?source=share
Sonic Underground’s Birthday Gig
This is set in my Baby Tails Underground Au.
“Are you sure about this?” Sonic questioned as they drove the van onto the boat. His jade eyes locked onto the water like if he kept his eyes on it, the water couldn’t get him.
“Yes.” Sonia replied. “We need to make connections with freedom fighters in MegaMell and this gig is the perfect excuse to enter.”
“Plus, it pays!” Manic noted. “And with Sis’ spending habits, we could use all the rings we can get.” Manic put the van into park in their bay. He tapped his fingers on the stirring wheel. “Unless…” He grinned as his twin siblings mischievously.
“No stealing.” Sonic chastised. “Unless it’s from Buttnik. But otherwise, no stealing.”
Sonic was happy not to see the water anymore. But he frowned as he still felt the water shift the boat.
“Don’t fret too much.” Sonia assured him. “The trip will only be a few hours.”
Sonic glared into Sonia’s green eyes. “Days.” He remarked and paused before adding, “I read the pamphlet.”
“Only 3 on this boat.” Sonia stated as if it was a good thing. “That’s a lot faster than most other boats.”
“That means it’s fast, just like you.” Manic clapped a hand on Sonic’s shoulder.
“Just try not to make Tails fear the water too.” Sonia pleaded in a whisper. “He mimics you the most.”
“Relax sis,” Manic assured her. “You’re not the one little dude will claw to death during bath time.” Manic gestured to himself and Sonic with his thumb. “That’ll be us.”
Sonic rolled his eyes as he got up to check on the toddler in question. Tails had managed to get out of the car seat Sonia had gotten him and was sitting in Manic’s bunk. The brown kit was surrounded by random parts. He had managed to build some kind of bubble in the bed.
Sonic arched a brow at the fox. Black eyes that hadn’t changed out of baby colors looked up at him and then his work. He held a finger to his mouth with a toothy grin. A sign they had taught him to mean, “Please don’t tell on me.”
Sonic kept a stern look for a moment before smiling and shaking his head. He could never really be stern with the kit. “We’ll be on this boat for a while, little bro.” He began helping the fox remove the random tools and things from the drummer’s bunk bed.
After 3 days, Sonic was relieved to be getting off the boat. He was going stir crazy and there was only so many times he could run around the boat. Thought he was distracted for a few hours when they realized that Tails had made a little drill tank that the fox swore could swim in the ocean. Sonic was not testing submarines made by a kit that only had space for said tiny kit.
Nope!
Nada!
And thus, the fox pouted about not benign able to take his newly built toy into the ocean. His displeasure was made worse when Manic and Sonia told him no too.
“Now,” Sonia and Manic checked the map. “Our lodgings for the gig should be down this road.” Sonia pointed as Manic followed the road on the map with his finger.
Manic nodded. “Let’s juice and jam then.”
The triplets quickly learned that cars drive on the other side of the road here.
“Perhaps we should get a traffic rule book?” Sonic suggested as he buckled Tails into the car seat again. Manic simply responded with a thumbs up. His brown eyes locked on the road.
Once they arrived, Sonia checked in to the rented house they would be staying in. Sonic had gone on a run while Manic fed Tails a snack of cinnamon apple sauce. The fox was happy to enjoy mushed up apples.
Once they were settled in, Sonia called to order a meeting.
“So goals!” She stated simply. “Preform our gig and make contact with any freedom fighter groups in Mega Mell.”
“Luckily the gig is preforming for a birthday party." Sonic noted.
“So happy birthday and a few other songs,” Manic noted with a grin.
Sonic nodded. “Plus considering this is for someone who is a fan of us, we might meet some freedom fighters there.”
Sonia nodded at that. “Did you notice any thing while on your run?”
“Surprisingly, there isn’t a lot of Robuttnik’s influence around. But I’m sure it’s somewhere.” Sonic replied as he combed out Tails’ fur. Tails watched the brush with narrowed eyes. His tails swishing in a pattern that warned if not careful, the fox would pounce or swat at the brush.
A day later, Sonia instructed Tails to stay seated at a table in a local diner so the triplets could talk with the man who hired them.
The blue hedgehog was several shades lighter than Sonic. He was a pastel sky blue as he walked up to the table the triplets were seated at. Tails noted that the new guy smelled of wood and trees.
“Hi, I’m Rob. I’m glad you were able to make it.” He waved at the trio. He leaned down to meet Tails’ eyes. His eyes were a pale emerald. “I’m the guy who hired your friends to preform for my beloved’s birthday. Do you like cake?”
Tails thought for a moment before holding up a dinner mint Sonic had snagged him from the host stand.
Rob laughed. “I’ll supply you with a bag full.” He turned to the trio. “I really appreciate you making the trip here. My beloved is a huge a fan. Your performance will make her day.”
“Are there any specific songs we should play?” Sonic mused.
“She’s a fan of when there’s a will, there’s a way, Society Girl, Cosmic Dance, and a few others.” Rob pulled a piece of light pink paper with strawberries along the border. He flipped it open to check. “She wrote them down for me.” He gave a cheeky grin. “She thinks I’m hiring a DJ to play tracks from a mix tape.” He handed the list over.
Sonic took it and skimmed it. The eyes were dotted with hearts and bubble period dots. He handed it to Manic to look at. “How old is your girlfriend turning?”
Rob tilted his head in confusion. He stayed confused for a moment before it dawned on him. “Ah. Beloved is a term of endearment for younger relatives.” He gave an awkward laugh. “My beloved cousin is turning 7. She has great penmen’s ship already.”
“It’s neater than mine.” Manic complimented.
After their meeting, Rob showed them where in the diner they could set up their instruments and do test runs with the owner of the diner.
Two days later, the crew were hiding behind the stage. Mics were all set up and tested. Tails sat at the seat before Manic’s drums, spinning slowly.
“Alright, we want the speakers here right?” Sonia double checked the hand scribbled floor plan before moving the speaker with a hand truck.
Sonic had quickly set up the lights before stopping by Tails. He checked the kit for injuries before reminding him NOT touch the drum symbols.
Tails nodded in understanding. Drum symbols were very sharp. He had learned that the hard way while running away from being brushed. Tails’ eyes caught of something pale pink in a corner of random props. He glanced up at the triplets. They were doing warm ups and double checking everything was where it should be.
That left the fox free to check it out. He used his tails to soften his landing to the floor. He had learned the art of stealth long before meeting the triplets. So long as Sonic didn’t notice, he wouldn’t be caught.
Tails grinned to himself as he went to the corner of props. It was close to the stage left entrance by the kitchen. Tails found a pink hedgehog in a yellow tutu rummaging through the box of props. He glanced up at the triplets. They were doing warm ups and double checking every thing was where it should be.
That left the fox free to cheek it out. He used his Tails to soften his landing to the floor. He had learned the art of stealth long before meeting the triplets. So long as Sonic didn’t notice he wasn’t where he was before, he wouldn't be caught.
Tails grinned to himself as he went to the corner of props. It was close to the stage left entrance by the kitchen. Tails found a pink hedgehog in a yellow tutu rummaging through the box of costumes. Tails paused before tapping his foot loud enough for her to hear.
Emerald green eyes turned to him. She was confused but then gave a bright smile. “Hi! I’m Amy. Are you here for the birthday party too?”
Tails responded with a nod. Most people called him a freak for his twin namesakes. Either this girl was like the triplets or she just hadn’t noticed them yet.
“Oh goodie! I’m looking for costumes to wear.” She linked arms with the fox and brought him over to look at the box. Tails noted that she smelled of the artificial strawberry shampoo Manic had used on him a few times. “I’m wanting to dress like a knight.” She pulled out a toy sword. “They have all kinds of outfits in here. What would you like to dress as?”
Tails thought for a moment before shrugging.
“Well, who or what do you think is cool?” Amy beamed as she pulled out a tall pyramid princess hat from the box.
“Sonic,” Tails signed with a big smile.
“Sonic the Hedgehog is very cool!” Amy exclaimed. “He’s a great singer and a freedom fighter too!”
Tails nodded as the girl gushed about Sonic. She was a big fan of the Blue Blur.
“Nothing in here really screams Sonic,” She pouted. “Oh!” She suddenly lite up with joy. She linked arms with Tails as she pulled him along. “I have a Sonic shirt. I’ll let you borrow it! If you’re okay with it, I’ll even style your hair so you can really pull off the Sonic look.”
Tails allowed himself to be dragged along by the cheerful girl. She pulled him to a table in the center of the diner. The table that was set up for the birthday girl. She reached into a floral book bag. She pulled out a few shirts bearing Sonic’s face on them. Each was slightly off in it’s own way. Though Tails found the offness funny.
“Rob says the DJ will play some of Sonic Underground today. So I brought some of my favorite shirts since I couldn’t decide which one to wear. Pick whichever you want.”
“You’re the birthday person?” Tails signed.
Amy nodded with a bright smile. “Yep!”
“Happy birthday.” Tails signed before looking at the shirts more closely. He chose the 2nd closest to Sonic’s actual appearance. He picked the one most like Sonic and put it in Amy’s hands. “This one looks the most like Sonic, so you should wear it.”
“Really? Thank you!” Amy beamed as she put the shirt on. Once Tails had the loaned shirt on, Amy pulled out a small comb. “Now it’s time to style you.”
Tails stared at the comb with apprehension. He did not like having his fur brushed. But she was the birthday girl. Sonia and Sonic had each told him that you let things slide for the birthday person. Tails could let some fur brushing slide. She was the birthday person after all. Plus, she loaned him this nice shirt.
Amy happily chattered away as she styled his fur to look somewhat like quills. Tails was used to listening to Sonia gossiping. Amy’s way of gossiping was different, but amusing. Less romantic drama and more sweet stories of loved ones.
“Tails!” a voice yelled for the fox. Everyone looked up to the side door of the kitchen to see a blue hedgehog frantically looking into the kitchen. “Miles!” He hissed in a stern tone. The tone said if the fox didn’t stop his houdini act, he’d be lucky if the lecture ended within an hour.
Tails put two fingers in his mouth and made a whistle.
Blue ears flicked towards him before the Blue Blur’s head turned and jade eyes laid onto the two tailed fox. In a nanosecond of a blur, Sonic was in front of the fox. Right foot tapping away with hands on his hips. His eyes scanning the fox over for injuries. Then his eyebrow arched as he noticed that Tails was allowing someone to brush his fur.
The girl didn’t like Sonic’s tone as she hugged Tails to her. “Do you know him?” she whispered in his ear.
Tails nodded. “Birthday girl,” Tails signed pointing to Amy. “Big brother,” he signed before gesturing to Sonic.
“You left without a peep.” Sonic poked the fox in the chest. His anger and worry having dissipated.
“I took him to dress him up for the party.” Amy bowed her head. “But now you both get to be dressed up as Sonic the Hedgehog!” She beamed.
Sonic paused for a moment. “Ouch.” he thought to himself. The kiddo thought he was an actor. “Thanks kiddo.”
“I’ll stay here while you and the others perform.” Tails signed with a smile.
Sonic blinked several times in surprise. Tails was a shy kid. He hid from acquaintances most of the time. His jade eyes moved to the pink hedgehog. She was happily attempting to style the kit’s fur into quills. She seemed bubbly and excitable. And possibly loud when very excited. He looked between the two over and over for a bit.
Was she magic?
Tails barely let him or his twins run any comb through his fur. Sometimes even fingers were a no go. Yet here Tails was. Being dolled up like a pageant queen with no complaint, growl, or frown.
Tails looked at him with a sweet pretty please look.
“If you get overwhelmed, you come straight to me or our other siblings.” Sonic stated as he patted the kid’s shoulder.
“What’s happening?” Rob walked up to the table from outside.
Amy beamed at him. “I made a new friend! They’re fans of Sonic too!”
Rob smiled as he nodded. “That’s great beloved.” He pulled out a mint from his pocket. “I also remembered to get you one of those candies you like.” He held the mint out to Tails. Tails looked at it before picking it up. He smelled it.
“Do you like mints?” Amy asked.
Tails nodded. “Want to share?”
Amy shook her head. “I’m good. I prefer strawberry bon bons. That one is yours. So enjoy it.”
Tails nodded as he opened the candy and popped it into his mouth.
Rob handed Amy a bon bon. “I see the kids have already become friends.” He turned to Sonic.
Sonic nodded. It was surprising how quick Tails had made a friend.
“I’ll stay here with them while you get ready to perform.” He leaned in. “It’s so funny how she hasn’t noticed yet.” He whispered to Sonic while holding back a laugh.
Sonic returned to backstage, watching Tails and Amy talking about Sonic the Hedgehog amongst themselves. Manic and Sonia were watching from behind the curtains.
“Did Tails get a crush?” Sonia chuckled.
Sonic froze midstep. “No.” He denied. “He’s a baby. Babies are too young for crushes.”
Sonia nodded as she held back a laugh. “When you get your first crush, maybe you’ll think differently.”
“Nah,” Manic shook his head. “Sonic’s only loves are running and chilidogs.” He patted Sonic on the shoulder. “Plus it’s rad little dude made a friend. He can’t hang with us all the time.”
Sonic nodded. “I know.” He glanced back. “I’m just feeling a little lonely without the little guy.”
“Welcome to they’re growing up blues, bro.” Manic joked as he rubbed his back. He too felt awkward about the idea of Tails growing up. He just hid it behind jokes. Plus it was good that he made a friend even if it was odd how fast it was compared to when they had taken him to meet other kids his age.
The show began without any issues. It took the now 7 year old pink hedgehog half a song to realize that they were the real deal Sonic Underground.
Her excited squeal was funny to the triplets. Tails didn’t find it so funny. It hurt his ears. Amy apologized to him when she realized. She fished out a pair of headphones from her bag and placed them on the fox’s ears to dampen the loud sound. She carefully placed the long wire under the shirt so it wouldn’t get caught on any thing.
“Do you want to dance?” Amy asked with sparkly eyes.
Tails shrugged. He wasn’t much of a dancer. He still followed her to the dance floor they had set up.
Amy took it up on herself to teach Tails some of her signature dance moves and got some of the other kids she had helped dressed up to teach each other their dance moves. Tails found himself having a blast. He was introduced to several other of the pink hedgehog’s friends.
After the party, Tails stayed to help clean up. Amy had stayed to swoon over Sonic and ask a kajillion questions. She asked Sonia and Manic a few questions too, but most were for Sonic.
“Beloved make sure you clean too,” Rob gave a light order.
Tails liked Rob. He snuck the fox mint candies for being well behaved.
“I am cleaning,” Amy stomped her foot with a pout. “I cleaned and wiped the tables really good.”
“Really? I shall check.” Rob mused with a smile.
A thought struck Tails. The fox walked over and green eyes turned to him. One set jade and one set emerald.
“What’s up little bro?” Sonic smiled at him.
Tails nodded at his brig brother before turning to Amy. “Do you know of any freedom fighters local to this area?”
“Are you trying to make a network with other groups? Amy beamed as she bounced on her heels.
“Tails.” Sonic pulled the fox away from the pink hedgehog. “You just can’t go asking people that.”
“I mentioned freedom fighters first though.” Amy pouted as she stood by Sonic’s side.
Tails waved from where he was being held in Sonic’s arms to let the pink hedgehog know he was fine.
“I don’t think there isn’t a person on Mobius who doesn’t know Sonic Underground are also Freedom Fighters.” Amy pointed out.
Sonic nodded with a smile. “That is nice to hear.”
“Plus I do know some local freedom fighters.” Amy beamed with a cheeky grin.
“Is there any way you’ll tell us?” Sonia asked Rob.
Rob paused for a moment. He looked at his beloved 7 year old cousin.
“I’m the negotiator.” Amy raised her hand and waved it around.
“I shall conceded to you then.” Rob bowed. “You can’t ask the man for marriage.” He tacked on in Latin.
Amy frowned at him. She looked away as she thought of another option. She looked back at her cousin hopefully. “A kiss?” She asked hopefully in Latin.
“No.” Rob responded simply.
Amy deflated. She quickly perked up with a bright grin.
Rob rolled his eyes. “Beloved,” He warned sternly in English before switching to Latin, “You can ask for a high five at most. No other physical contact.”
Amy nodded. She didn’t like how contrived her cousin was being, but the young girl would make do with what she could. She pulled out a small sketch book from her bag. “I would liked an autograph from each member of Sonic Underground.”
She beamed at her cousin who nodded in approval. She quickly presented the book to Sonic. “I’ll get you each a marker.”
She raced back to her bag humming to herself.
“She’s certainly lively.” Manic laughed.
“Yeah, the little rascal keeps us on our toes,” Rob nodded.
Amy quickly returned with a color marker for each person. Blue for Sonic. Green for Manic. Hot pink for Sonia. And an orange one.
“Who is the orange one for?” Sonia inquired sweetly.
“This is for Tails!” Amy beamed.
The triplets shared a look.
“Tails doesn’t know how to write yet.” Sonia stated. “All you’ll get is some scribbles.”
Amy tilted her head in confusion. She could have sworn she saw him help with a crossworld in one of the activity books. Her emerald eyes scanned the triplets’ faces for a hint of falsehood. They 100% believed Tails could not write.
“I can teach him.” She offered. She beamed at the fox. Maybe he was too shy to show off how smart he was, so she would give the fox an out.
“That’ll take a while,” Sonic pointed out.
Amy smiled wide. “All the more reason for me to teach him how to write! Writing letters are so much fun!” She bounced with joy.
Tails wiggled out of Sonic’s hold and looked at the page in the book Amy chose for him. He held out his hand for the marker she held.
The pink hedgehog happily handed it to him as she babbled on about how great it was to write letters to far away friends. Tails held the marker how he saw Sonia hold it several times before. She had the most legible handwriting of the triplets. His handwriting was shaky but it was readable.
The triplets stared in confusion as they watched the fox carefully and slowly write a name on the page in the sketchbook. He added a little stick figure drawing of himself next to it. The fox had seen Manic draw a stick figure of himself next to where he signed his name and the fox liked it.
He handed the sketchbook and the marker to the birthday girl. She beamed as she looked at signature on the page.
“Where did Miles come from little bro?” Sonic asked as he leaned down to the kit’s height.
Tails tilted his head. He thought for a while before signing. “My name.”
“Why didn’t you tell us about it?” Manic probed kindly.
“No one asked.” Tails responded with a shrug. His tails curling around his body.
Manic nodded. Made sense. Maybe they should ask the toddler some questions. They just never considered to do so.
Sonic took note of how the kit was being nonchalant, but his tails curled around his small body like a protective barrier. He had a feeling that someone HAD noticed the kid could read and they did not have the usual reaction to the fox. The lead guitarist wished he could time travel to beat up whoever had scarred the small child.
Sonic fought the urge to glance at Sonia. She’d have this knowing look and would probably go on a rant about who hurt the little kid. She’d questioned Sonic on where he’d found the kit so she could track the jerks down to give them a talking to. And all Sonic would be able to give her was, “I found him in a trash can.” Just like he’d said when he first brought the tiny fox home.
Sonic felt it would be best to switch topics. He messed with the fur on the fox’s head. “So now that you have the autographs, can you tell us about the local freedom fighters here?” Amy nodded as she bounced over to her cousin’s side. She threw a puff of glitter she must have picked up along the way. “Ta-Da~!” She sang while beaming with pride. “Rob is one of the leaders of a local chapter.” She danced around Rob.
Rob had no reaction aside from coughing at the glitter that made it to his airways. He was happy to watch his cousin dance around him. Her getting Tails to do her little dance around him did, however, make him feel like he was going to be sacrificed. Maybe he should have brought more candy.
Author’s Notes:
I began writing this on 9/24/2026 and finished writing it on 11/6/2026. I had a blast writing for this AU. I have had people ask for more stuff for my Baby Tails in Underground AU. I’m currently working on a comic taking place in this AU that I’m hoping to have done sometime next year so I can take it to cons. I’m wanting to bring printed copies of it to give out while there. So if you run into me, come say hi and get a comic or an art print from me.
I chose to change the name of the area Amy Rose and Rob are from to just create a bit of distance from the Archie canon. I took the name from Mag Mell a place in Irish Mythology. Mega comes from the Mega Drive and the fact that Mega was part of my original online name.
You'll be able to get the Epub and PDF versions of this fic to download and read offline from my KoFi.
