This is a story set after the Season 3 Finale of Sonic X. Tails is distraught over Cosmo's death, he stops building and tinkering with machines. Everyone is worried and upset over him, so they get help from an unlikely source, Dr. Eggman.

Operation: Revitalization

"Hey, what are you guys doing sitting around Tails' room?" Sonic asked.
"We were just worried and we wanted to cheer him up" Amy replied.
"He hasn't even left the room since the accident" Knuckles chimed in. Sonic whispered to Knuckles his plan.

"Okay, stand back" Knuckles stated. Amy, Sonic and Cream walked until their backs were against the wall opposite from the door. Knuckled violently swung his arm and gave the door one good punch. The door flew off it's hinges and slammed against the bare wall. This startled Tails.
"Great, now how are you going to fix this?" Amy replied, pointing to the broken hinges.
"Tails! Come on! Let's go!" Sonic asked.
"No" Tails replied, ducking his head under his pillow.
"This is ridiculous! You haven't come out of this room since Cosmo died!" Sonic replied, angrily.
"It's all my fault" Tails replied, softly.
"It's not. You didn't know she needed to do that. You were only helping her" Amy replied, calmly.
"Then, how comes, I feel so guilty?" Tails whined.
"Probably because you had feelings for her. She returned them, and when you did that, that's why you felt guilty" Sonic replied.
"I wish there was something we could do" Tails said.
"Wait! I have an idea!" Sonic replied, dashing out of the room.

A little while later, Sonic returned with the flower pot Tails had in his workshop.
"What do you think this will help me?" Tails replied.
"Simple. There has to be some of Cosmo's DNA in here right?" Sonic asked.
"Right" Tails simply replied.
"Well, we'll give it to someone who can extract the DNA and recreate her" Knuckles chimed in.
"I was supposed to say that" Sonic replied quietly to Knuckles. Sonic and Knuckles slipped away while Amy stayed behind to keep Tails company.

Dr. Eggman's Lab

"For the last time, my face is not that BIG!" Dr. Eggman shouted. Suddenly, the door exploded open.
"Sorry for crashing your party, but this is urgent!" Sonic shouted. He hoisted the flower pot up.
"What do you except ME to do?" Eggman questioned.
"You have the DNA Revitalization machine, correct?" Sonic asked.
"Yes, I still do. And it works perfectly" Eggman replied.
"Then regenerate Cosmo for Tails" Sonic replied.
"This will take a while. In a few hours, I'll give you a buzz saying the process has been done. Make sure Tails doesn't seem Cosmo until I give you the buzz. Got it?" Eggman stated.
"Got it" Sonic and Knuckles both stated.

Several hours later.

"Wah!" Tails whined.
"Tails! You've been whining for 4 hours! Take a break!" Amy replied.
"What would Cosmo say if she saw you crying?" Knuckles asked. Sonic felt a buzz. He knew she was coming.
"I would say, 'Get up and stop crying'" A familiar voice said. Everyone turned and gasped.
"Oh my gosh!" Cream shouted, excitedly. Cream's Chao tugged at Tails' tail, trying to get his attention.
"What do you want?" Tails replied. He fixed his gaze on the the female in the doorway.
"Cosmo?" Tails replied.
"Yes, it's me" Cosmo replied.
"It's a...miracle" Tails replied.
"And to think, we were able to recreate her from a simple little bud" Sonic replied quietly.

It's a TailsxCosmo oneshot. What would (sorta) happen if Tails was upset and Sonic and the gang decided to try and bring back Cosmo.