Hanji stood in her lab, slowly shaking a test tube back and forth. The blue liquid inside sloshed against the glass as it changed into a sparkling purple. She smiled to herself and held the tube closer to her eyes for further examination. Once she deemed it complete, she inserted the liquid into a syringe and headed outside.

Bean looked to be sleeping in his shackles. Hanji smiled at her 'child' before gently injecting him with a small amount of the new concoction. She watched with childish glee as her experiment proved a success. But, that was on a titan. The formula she created was for humans. Or should I say, one human in particular. She nodded with determination before sneaking into his cell and injecting him in his sleep. The plan was now in action.

She wandered the grounds the next morning looking for her...subject. She checked everywhere. His cell, the mess hall, Levi's office. The only place left was the training grounds. She made her way there in a sort of power walk in hopes of catching him before he left. If he was even there to begin with.

She reached her destination to find...nothing. He wasn't here. She scowled deeply in thought and disappointment. Where could he be? She stood there baffled for a few moments. "Hey, shitty glasses, what are you doing?" Hanji jumped at the new arrival before turning around. Her scowl still held in place. "Have you seen Eren?" Levi tilted his head in confusion. "Wasn't he meant to be in your lab this morning?" Of course! She snapped her fingers and began walking. Levi watched a moment before letting curiosity take him.

They arrived at the lab to find Eren taking off his shirt. Levi's eyes widened at the cadets actions. "Hey brat! What are you doing?!" The piece of clothing was fully removed and Levi felt his breath catch. Eren turned around with an innocent gaze. "I thought Hanji said I would be getting a check up today. Was I wrong?" Hanji couldn't help the wide, open mouthed smile spread across her face. "S-Stop staring..." Eren trailed as his face turned red from embarrassment. Levi stepped forward, eyes still bulging out of his head. But now they were accompanied by pink tinted cheeks. "Eren...what, are those?" Eren looked confused so Levi pointed to the top of his head. Not understanding the situation, Eren reached on top of his own head. His hand touched something and he froze. His eyes inflating like balloons at the sudden addition to his body. He ran to the closest reflective surface and stared at his new features. Meanwhile, Levi's eyes seemed to widen more and his cheeks darkened. "No way..."

Eren was too busy staring at his reflection to acknowledge Levi's whisper. Nor did he hear the footsteps Levi took to end up behind him. Deeming her work done, Hanji left the lab with a wide smile on her face.

Levi reached out a hand and grabbed Eren's new limb. Eren jumped and turned around to find a hand on another new addition. He was gob smacked. How had this happened? He didn't understand. Then he heard the door close and figured it out. Apparently Levi had as well. "Thank you Hanji." Eren snapped his eyes back to Levi who now wore a mischievous grin. Eren gulped loudly. "So Eren, how's the tail feeling?" Eren's face began to burn once more as he tried to pry his new cat like tail out of Levi's hand. He managed to break free, but at a cost. The hand that was trapping his tail was now reaching up to scratch behind his ears. Rubbing nicely against the fur at the bottom. "Hanji made you a neko. How nice of her. This should make things...interesting." Eren's face burned a little more with each passing word. He was intrigued but scared at the same time. The tone his captain held made his voice husky. Behind the closed doors of the lab, Eren soon learnt exactly what Levi meant. And boy did it last a while.