AN: Response to a prompt on snkkink "Maybe someone tells Eren that he is similar to a dog, and transforms with that in mind, then when he comes out, he has dog ears and a tail, and it's just so adorable, and someone finds it really hot and they yiff. bonuses: -that someone is rivaille or jean -mikasa pets his head a lot -sensitive behind the ears -leg humping"

May or may not continue. If I do I wanted to have somewhere solid to do so instead of posting on snkkink, and also, if I do it may contain potential spoilers because I've read the manga which goes a few episodes ahead of the anime. (no ending sadly)

Mikasa keeps her face carefully blank as she watches her surrogate brother pull himself out of the steaming Titan's body, making a mental note that the next time Hanji didn't have supervision that she would never let the crazed scientist anywhere near her brother. Especially not Hanji and Jean together, because, while in hindsight it should have been obvious what a terrible idea it was, it hadn't seemed that bad of a thought when Hanji had first wandered up to them in the morning and explained she wanted to have Eren experiment with his titan form a bit that day.

Admittedly she did have her reservations about doing anything with Hanji while Corporal Levi and his squad weren't around, but the Scientist had shot down her concerns with the main point that Eren's control over his titan form had blossomed magnificently, and that between her, Armin, Mikasa, and Jean, it wasn't like Eren would be able to do any damage if he did lose control. Of course, Jean had just been an innocent passerby when Hanji had grabbed him, and there had been the small issue of his ten minute struggle before Eren finally goaded him into agreeing, but…

It was a rather shocking site to see her brother in the state he was now. She'd made the mistake of assuming that nothing could be as surprising as seeing him emerge whole from the titan body back in Trost, but this was almost right up there. This being the fact that two dark brown, furred, triangles sat at the top of Eren's previously uninteresting head, the bases blending into the teen's hair naturally. It wasn't until they twitched to the sound of a bird's call that she realized they were ears. And then, once Eren pulled himself out of the titan body some more, she also realized that he had a tail.

The term pregnant silence had never really held much meaning to Mikasa before, but now, in this moment, she knew exactly what it meant. A glance to her left revealed a speechless Armin, who looked like he didn't believe what he was seeing. She then glanced to her right, towards Jean, and wasn't too surprised to find that while he appeared shocked one corner of his mouth appeared to be twitching, as if he wanted to break into a smirk. It wasn't hard to guess why, considering that Eren now had some dog like attributes, the very thing Jean had just been teasing him about before he turned.

Her attention turned back to Eren, who was just managing to finally yank his left foot free of the titan corpse. It wasn't until he did that the silence hit Eren, and the titan-shifter looked at the group of four in front of him in a baffled manner, eyes resting on Hanji much longer than any of the others. Eren was more than a bit surprised that Hanji hadn't yet rushed over to the now disintegrating titan body to try and climb inside it like the last few times, or that she wasn't gushing over what good notes she had gotten or how well he had done that day.

"Eren," Mikasa called, and her brother's attention snapped to her immediately. She held out a hand towards him, "Come."

Eren wasted no time in going over to his sister, although he was still confused. He took the hand that was held out to him, their fingers easily and naturally interlinking as Mikasa stared intensely at him. He stared back at her, trying not to twitch under her scrutiny, because she did this often enough when he came out of his titan body to make sure he was okay, but the silence was getting to him and he didn't know why Jean was covering his mouth with a hand.

Had something gone wrong? Maybe his shifting had finally taken its toll and some part of his body had changed even though he was outside of the titan husk. The thought terrified the titan-shifter, but he tried to convince himself that he had just missed picking off some of the yuck that clung to him so thickly, and that it was most likely on his face, so he started to reach up so he could find it, but Mikasa's free hand darted up to the top of his head.

"Good boy."

It wasn't the first time that his hair had been ruffled, but it was unusual for Mikasa to do it because she knew how much he hated it. Except this time it was different because it felt really good for some reason, and Eren was absolutely baffled by that even as he tilted his head into Mikasa's scratching fingers. She just wondered if there was any way for Armin to acquire them too, because then both of the members of her family would have them, and Mikasa would be lying to herself if she didn't admit that the idea was an adorable one.

Eren could see his sister smirk at him, but he ignored her in favor of just enjoying what was now undoubtedly petting. He knew that he should probably be embarrassed that she was doing this in front of Hanji and Jean of all people, because Armin was family and he didn't count, but he really couldn't care less at the moment. The teen soldier let out a hum of approval when Mikasa twisted her fingers just right, but was soon distracted by something he could see darting in and out of his peripheral vision.

Whatever the thing was, it was fast. It also seemed to not bother Mikasa in the slightest, which told Eren that he was safe because as annoying as the girl's overprotectiveness could be at times, he knew he would never be hurt if she could help it. But whatever the damn thing was it was getting annoying, he could just feel it darting behind his back, swinging back and forth apparently since it seemed to go from left to right. Eren reached back and grabbed the offending object, pulling it forward and staring at it in surprise.

A tail. It was a tail, and when his eyes followed along it the tail led to behind his back, so he felt along it with his free hand and sure enough…

"WHAT THE FUCK?!"

Then and there Eren Jaegar swore to himself that no matter how much goading Jean did or how much Hanji insisted that it was a great idea his titan form play 'fetch', he was never going to bite his hand and think 'turning into a fucking titan to be a dog' again. His own scream seemed to finally send Jean into complete hysterics, but he ignored the bigger teen's gasping of "you're an actual fucking dog!" to instead watch as Armin came up to him.

Armin was smart, smartest out of all of them despite how kickass Mikasa could be, so surely he'd have some solution for this mess. The blond just stared at Eren for a moment before reaching and pulling lightly at his tail, examining it with his bright blue eyes in interest. The titan-shifter groaned, reaching up to feel at his head because Mikasa had yet to remove her hand, which meant that most likely there was something there. Mikasa flicked one of the dark brown dog ears gently, and Eren's face darkened when he felt it twitch in response.

Armin was unable to resist reaching up and adding a third hand to the top of Eren's head. He scratched the ear that Mikasa wasn't paying attention to, and the girl took that as her cue to continue her attentions on the other. This seemed to have a remarkable effect on calming the irate titan-shifter down, who's murderous look quickly changed to a slightly dazed one, and Armin and Mikasa shared a pleased look. Both knew it would be a great advantage to them if they could get Eren to calm down just by something as simple as reaching up and giving him a good rub behind the ears.

Jean finally wandered over, having composed himself a great deal, although he still eyed Eren with amusement. "Did you really not feel those things? The ears have been twitching like crazy since your head popped out of the titan body."

"No, uh…" Eren appeared somewhat dazed, before he caught on to why and slapped Armin's and Mikasa's hands away in annoyance. "Outside of it feeling nice for them to be touched I never noticed anything odd. I'd try shifting again but I'm too tired for that, and I'm too afraid to ask Hanji."

It was rare for the titan-shifter to admit he was afraid, much less in as calm as a tone as he had just used. Mikasa, Armin, and Jean had all had their backs to the Scientist, and while they had noticed she was silent, which was very unusual, they hadn't paid her much thought. Except for now, because all three had to look if she was unnerving Eren of all people when he was remarkably good at dealing with all her craziness.

One look at Hanji had Armin stepping back a bit as if he could hide behind Eren, but it also had Mikasa stepping in front of them both. The scientist appeared totally unresponsive, a grin on her face reminiscent of the one Eren had worn when he had first woke up from his titan form, glasses glinting dangerously and blood dripping from her nose. Even Jean shuddered.

"I vote we get out of here, Commander Erwin might be done with the meeting by now…" Armin suggested, turning his eyes to the much more interesting sight of Eren's tail and he wondered just how it came to be.

Eren and Jean agreed immediately, and all of the teens set off back to the Recon headquarters, but not before Mikasa walked up to Hanji and shoved her over, muttering as she did so before pulling up her scarf to cover up the bottom half of her face. All three boys knew better than to say anything even as Eren felt a slight twinge of guilt, but a second look at Hanji's face made him feel better. He agreed with Mikasa completely if she wanted to make sure that no one looked at him with such an indecent look ever again.