Alright, this is my first attempt at a multi-chapter fic! All of the others that I've written are one shots, so this is really new to me. Chapters might start out short, but I'll try and make them longer as they go. Hope you enjoy and I'd love to know what you think!

Why do I feel so weird...? Hiro wondered groggily, eyes still closed. It was as if he were paralyzed and not able to move, which was really freaky.

But that was just it. He couldn't feel a thing, except a strange and uncomfortable sort of heaviness.

Was he in the hospital for some reason? The young genius certainly hoped not.

But then again, how could he have ended up in the hospital if he had Baymax with him? The robot always made sure that he never got hurt; his health was the nurse's only concern, after all.

Hiro tried opening his eyes again, growing more worried and frustrated when he couldn't—they just seemed to be stuck together with duct tape. He laughed at the memory of teasing Tadashi about how duct tape had already been invented, but soon realized that he couldn't laugh, either.

Okay. What was wrong with him? Did Aunt Cass know? Maybe not...

The last thing he remembered was being in the lab at school with Baymax and the rest of the team. It was late, and he was working on a very important side project that he'd wanted to test out. Everyone had left when they couldn't get the prodigy to stop working, so in the end it had just been him and—of course—Baymax, who had refused to leave his side ever since the incident with Callaghan and his daughter.

Hiro assumed that he was still in the lab, so he attempted to open his eyes once more to see if he was right.

The boy sighed in relief when his eyes finally opened and he discovered that yes, he was still in said lab.

Wait. He was on the floor in the lab.

Something must have happened to the machine again.

Unbelievable. I was so close to getting it done...

It was just then that Hiro realized he hadn't sighed at all. He wasn't breathing at all.

A horrible thought struck him and his eyes widened.

Am I dead?

Panic overtook him and he grasped at his throat when hyperventilating didn't work. He was choking, but not really choking. He wasn't dying either though, which was great.

What the heck was going on?!

Hiro half expected Baymax to diagnose him with a panic attack, but he soon calmed himself down enough to realize that Baymax hadn't said anything at all about his condition, which had to be the weirdest thing ever despite the current situation he was in.

Hiro did his best to try talking through his constricted throat, looking worriedly around the empty lab at what appeared to be broken parts of his machine.

"B—Baymax...?" The teen said slowly. He blinked when a different voice came out. Had he heard right?

No, that wasn't his voice. It sounded too mechanical, too programmed, too...robotic.

Hiro's eyes finally rested upon the horrifying image of himself lying on the floor a few feet away, curled up into a ball.

The fourteen-year-old genius didn't need a mirror to know what happened.

He and Baymax had switched bodies.

Well at least I know the machine actually worked, now.