Princess Twilight Sparkle was working in her science lab when she heard a knock on her palace's doors. She quickly sent Spike to answer the door and bring her guests to her. Soon afterward, Spike walked in with Octavia Melody and Vinyl Scratch.
"What brings you here today?" Twilight asked.
"You see," said Octavia, "Vinyl's eardrums are down."
"That sounds bad." said Twilight, worried. "Is there anything I can do to help?"
"That's why we're here." replied Octavia. "We think you can help us. You see, Vinyl had an idea that you could shrink me so I could go inside her and fix the problem at source!"
Twilight raised an eyebrow. "That's a pretty crazy idea." she said. "But I assume you've thought it all through, being the good ponies you are."
Octavia nodded. "I'm ready to do anything for my best friend."
Twilight nodded and quickly picked up a book of magic spells. She looked through and finally came across a shrinking spell.
"Hold your horses, girls! Get it? Horses?" said Twilight as she charged up her horn.
Nopony laughed at her horrible joke.
Then, a charge from Twilight's horn shot into the air and hit Octavia. Octavia could feel her body getting smaller and smaller as she shrunk down to the size of a vitamin pill. To finish her part of the job, Twilight lifted Octavia into Vinyl's ear using her magic.
Now came Octavia's part of the job: find Vinyl's eardrums and fix them.
Of course, it didn't take long before Octavia reached the end of Vinyl's ear canal and found the eardrum. Octavia found that Nurse Redheart was more than correct about the damage done to the eardrum; there was a giant crack that went across the functional surface of it. Octavia began to try to think of a way to repair the damage. Octavia thought for a second, and then an idea flashed through her brain. She just happened to know that down in Vinyl's lower body was an extra bone that had grown into her due to a defect at birth. Vinyl didn't need this bone at all; its cartilage would be a perfect material to seal the eardrum crack with!
Now a new problem arose. The unneeded bone grew just above Vinyl's pelvis; getting down there would be difficult.