Story:
“Lysithea, it’s getting late, why don’t you”
“No Professor, I’m almost done.”
Byleth just sighed. She didn’t exactly mind working late. She had to plan her lessons for the next day anyways, but she didn’t like seeing her students push themselves too hard. Lysithea was brilliant, but that didn’t mean she had to finish her projects on the day Byleth assigned them just to prove it.
Some time later, Lysithea called over Byleth, apparently ready to test out her new spell. Recreating a shrinking spell without referencing a tome for assistance was quite the challenge, yet Lysithea was confident she had accomplished it successfully. She had memorized the necessary parameters to keep in mind, and had done the math to ensure proper she had fulfilled all the requirements that she was assigned.
“Okay professor. I’m going to begin the spell now. Are you ready?” Byleth just nodded, and braced herself for the spell to wash over her. The light from Lysithea’s spell erupted from the ground, and Byleth felt the magic was over her, she questioned to herself why she had thought a shrinking spell would make for the best assignment. She didn’t mind being shrunken, but maybe next time she’d make the assignment something that didn’t involve her being exposed to potentially dangerous and untested spells. As Lysithea began her gestures, Byleth felt herself begin to grow smaller and smaller, until finally Lysithea finished the spell, and Byleth was left at her new size.
“Yes!” Byleth heard her student exclaim. Apparently she was happy with the results. “Exactly a .15x height multiplier, spell completed in under 5 seconds, and target maintained full mobility! Looks like I completed it perfectly!” Lysithea crouched down next to her tiny professor, before carrying her over to the table so she could work on restoring her to normal.
Byleth was still a bit disoriented from being shrunken and picked up, but she was glad to be put down on the table. She watched at Lysithea stepped back, and prepared the counterspell. It did make her a bit uncomfortable being smaller than the candlestick she was standing next to.
As Lysithea recited the spell, Byleth noticed that she had made an error, and used the wrong calculation for her spell. Byleth was about to point out her mistake, but Lysithea finished the spell before she could say anything. Suddenly, instead of Byleth growing back to a normal size, Lysithea shrunk down to a size even smaller than Byleth!
Byleth decided it would probably be best to get Lysithea up on the table with her, so she lowered the chain of her sword to the ground, and lifted Lysithea up. Once they were both up, the two of them went over Lysithea’s notes, and realized that Lysithea had accidentally mixed up two variables when she crafted the reverse spell. So instead of growing Byleth, it had shrunken Lysithea.
The two shrunken women thought about what to do next. It was late on a weekend night, so nobody was going to be in to find them until at least the next morning. And even then they had to consider if they even wanted to be found in this embarrassing state. Lysithea was convinced that she would be able to fix her mistake and make a proper reverse spell, but the mistake she made was so early, that she would essentially have to recreate the entire spell, which had taken her all day to make the first time. And Byleth wasn’t exactly eager to be the test subject for another spell.
Notes are in the pinned comment because of the character limit in the description.