Hermione had never had to hide an idea in her mind before, never had to guard her thoughts to keep someone from pulling out her secrets and showing them to light. She had practiced Occlumency only when she was on the run to find horcruxes, thinking of the horror she might face should someone delve into her mind and see just what it was that they were searching for.
She'd never gotten particularly skilled at it, but still, some of the elements remained. In her mind's eye she took her thoughts and bound them up tight, weighed them down with a heavy promise of silence and then cast them into the chill ocean, still as glass, to sink deep deep where no one could find them.
It was, as one might imagine, quite difficult to keep a secret when you frequently shared mind space with two inquisitive individuals. Even with all her precautions, George had taken to absentmindedly rubbing the skin where his ear used to be, whenever he was lost in thought.
Hermione had, for several weeks, been working on something. She had snuck away for stolen minutes while the boys were busy with the shop, which was bustling now even on slow days. The idea had begun gnawing at her when she'd had a nightmare about the Triwizard Tournament of all things, old fears of Harry's demise related to more mundane causes, or as mundane as death by dragon can be.
She had remembered Alastor Moody, his roughly hewn peg leg clacking along the cool stone of the floors of Hogwarts, and his electric blue eye spinning and bulging too large in its socket. For all that magic could cure and heal ordinary injury, those injuries caused by magic, and dark magic in particular, were often simply left as garish scars. What muggle prosthetics lacked in function (for no muggle eye could see through walls, or the back of one's own head) they were vastly superior in returning to the user a sense of normalcy.
Those thoughts had sent her head spinning with half formed ideas of amplification spells and transfiguration, and before she had known what she was doing, she was pulling obscure texts from the shelves of Flourish and Blotts, and compiling cross-referenced notes regarding magical use of mundane materials.
The work was consuming, and when she finished she held in her hands a human ear, albeit molded from an inert plastic, which she knew to be an exact replica of the ear that had once rested on the side of George's head. She had drawn significant inspiration from her work with the Twins on other projects, had borrowed ideas for layering spells and permanent sticking charms and spells which could be activated with a word. The transfiguration alone, she thought, would have made McGonnagal proud, particularly given the plastic's resistance to spellwork.
For reasons which she suspected had to do with the finicky (read nonsense) nature of magic itself, she had struggled to bind the spellwork to the plastic, until she had placed a single kneazel whisker inside the folds of the material as she worked it into shape, and finally, the magic had taken hold. The idea had come to her in a moment of inspiration, and she had simply run with it, thinking of the sometimes slapshod method through which the twins' new inventions were born.
Now she had a prosthesis which was not only shaped like a human ear, but was warm to the touch, could be attached and unattached at a word and would grow in size to match the other appendage. She had also modified a hearing restoration spell (though wizards and witches are hardy folk, and rarely go deaf with age, they did have a tendency to deafen themselves in spell and cauldron accidents) which – along with the shape of the prosthesis itself – would help restore some of the hearing which she knew George had lost when he had been cursed. She knew he was partially deafened without ever having to ask, just as she knew that Fred's ribs ached just before it rained, and that they both craved sweets late at night.
When she held the final product in her hand, she was both exorbitantly proud and breathless with fear. It had been one thing, to imagine George's joy at being whole again, and another to present him with an unasked for gift which in many ways presupposed that he was unhappy. Still, she thought of the way the twins wore their hair now, long to cover their ears, and her resolve was strengthened.
She presented the gift to him without fanfare, placed in a simple box she found lying around in the shop, during a lull in conversation at dinner. He opened the box with only a little hesitation, only to toss it back onto the table, his face a mask of horror.
"What in the bloody hell is – "
"It's not a real ear!" Hermione spat out, her voice comically high. She cleared her throat and tried again. "I made it for you, to go over your..." she gestured vaguely at the side of his head. "Not because you need it! Oh bollocks, this isn't going well at all." She dropped her eyes to the table to avoid his stunned expression. "I made you a prosthetic for the ear that you lost, because you deserve to be able to forget for a while if you want."
She was studying the whorls in the grain of the wood of the table, waiting in vain for George to say something, but Fred exclaimed in fascination almost right away. He reached over and gingerly picked up the ear from where it had been flung free of the box.
"It's warm! And it feels like a human ear alright. Cor Hermione, that's brilliant." She flushed at the praise, and focused her attention on Fred, unable to meet George's eyes.
"It only ever stays the one temperature though. I tried to get it to adapt to the external temperature, but I couldn't get the spell right. It kept freezing or catching fire." George rose all at once, his chair scraping against the floor as he pulled away, then he marched around to where she sat and engulfed her in a hug.
"Thank you 'Mione," he whispered in her ear, and she could hear the grin in his voice. When he pulled away his smile stretched across his face in perfect mirror of his twin's and their happiness was infectious.
"Try it on!" she urged, explaining the mechanism of the sticking spell in partial sentences, which the boys still seemed to grasp. "The current command word is 'excitant' but you can change it to whatever you want. I would just pick something you won't use in common conversation. Don't want your ear popping off during tea." The wicked grin on Fred's face made it plainly clear that occasionally George's ear would be doing just that.