~Helium~

Summary: Happy April Fools' Day oneshot. Tadashi learns to never let Hiro near Baymax again. "Tadashi, it appears I am floating away."

It was Tuesday evening, both Hamada brothers were staying late at the university, focusing on their individual projects and working towards deadlines.

Hiro hiding in a corner of the hallway, waiting for Tadashi to leave his lab, bouncing on the balls of his feet with impatience. As soon as he saw Tadashi whistling, holding a cup of coffee, walking out of his room, Hiro almost yelled with happiness. He made a mad dash to his brother's lab; careful not to drop any of the items that were smuggled under his hoodie, and made a beeline straight for Baymax's case.

Hiro hurriedly got to work on his half baked plan, stashing everything at the back of Tadashi's desk and making sure it was well hidden. He ran towards the door to make his escape when he bumped into something sturdy but soft with an 'oof'.

'Tadashi…'

Hiro slowly looked up at Tadashi with a slight mischievous glint in his eyes.

"What are you doing?" Tadashi asked, narrowing his eyes suspiciously.

"Uhm, waiting for you." Hiro said, though it sounded more like a question than a statement. "Are you ready to go home?"

Tadashi grabbed his backpack and the keys to his scooter. "Sure." He took one last look around his lab, making sure that everything was safely put away in the correct places before turning off the light.

~The Next Day~

"Yow!" A yelp echoed through the hallways.

Tadashi poked his head round the door of his lab. The voice sounded familiar. He walked down the empty corridor and pushed a pair of doors open to see Gogo, Honey Lemon and Fred crowded around Wasabi, who was sat on a chair holding his arm gingerly.

Tadashi strode forward towards them. "What happened?"

"I was stupid, my measurements weren't precise enough." Wasabi mumbled.

"He was burned by his lasers." Gogo said simply.

Tadashi bent down to get a closer look at Wasabi's arm. "Let's go to my lab, Baymax will have something to treat your burn with." He ushered the entire group into his lab.

"Ow." Tadashi activated Baymax and walked to his desk.

"Hello. I am Baymax, your personal heathcare companion."

Tadashi was pulling a first aid kit from his desk drawers when he froze with confusion and looked back at Baymax. 'Was it me, or did his voice sound a little…off?' His eyes widened when Baymax spoke again.

Baymax looked at the Hamada stood to the side of him and blinked. "Hello Tadashi, what seems to be the problem?"

Gogo popped her bubblegum and jabbed at thumb at Baymax. "Why has his voice gotten higher?"

"It must have malfunctioned again!" (*1) Tadashi groaned as he dragged his hand across his face, beginning to feel despair that he would never get his robot right. "I'll fix it later."

"My systems are at one hundred percent." Baymax insisted in his new squeaky voice.

"Uh, sure, buddy." Tadashi smiled at his project. "Would you mind taking a look at Wasabi's arm?"

Baymax looked at the ground as he navigated his feet to step out of the charging station whilst Tadashi walked to Wasabi, helping him to cut away part of the singed sleeve. (*2)

"Hey guys, would you mind giving me a hand?" Tadashi frowned, wondering why his friends were stood as still as statues.

Fred tapped the older Hamada on the shoulder and pointed upwards at the ceiling. "Um, Tadashi?"

"Tadashi, it appears I am floating away." (*3) Baymax was waddling his legs frantically, trying to get across to his designated patient.

"What?!" Tadashi dropped the scissors he was using and leapt at Baymax, his hands latching on to Baymax's arm. But his efforts weren't enough to bring Baymax down and he, himself, was being lifted off the ground slightly.

"Hold on, Tadashi. Fred to the rescue!" Fred took a couple paces backwards and bent his knees before running to Tadashi and pouncing on him.

Gogo stared with a bland expression, her jaw moving up and down as she chewed her gum silently whilst Wasabi started to walk up to the pair of 'idiots' that were bobbing off the floor.

Honey Lemon walked over to Baymax's charging station to see what caused Baymax to act funny. She pulled the red station out away from the wall and peered behind it. There were two lines coming from the base and disappearing to the back of Tadashi's desk. She followed them until she found the offending objects.

Honey Lemon dragged two tanks out from behind of the desk.

"I think this was filled with helium" She examined them a little more closely. "It looks like Baymax was inflated with it."

Baymax was now firmly on the ground with Fred and Wasabi each hugging an arm. Tadashi readjusted his cap, amazed that it stayed on during the commotion. He crouched down, taking a look at the tanks of helium himself and came to the same conclusion.

He groaned. "Who would do that?" He dragged his hand down his face, pausing when it cradled his chin. Then his eyes landed on his calendar. A date was circled in red with an exclamation mark below it.

April 1st

Then it clicked in his mind. "Hiro!" Tadashi's hands were back on his face as he shook his head with a sigh.

Hiro was stood with his head peering around the door, trying desperately to suppress his giggles. His shoulders were shuddering with laughter as he wiped his tearing eyes. After taking some deep breaths and calming himself down, he stared back into the lab, wondering why everyone had fallen silent, but his view was suddenly blocked by someone.

'Oh no…' Hiro winced. He knew who it was before he even looked up.

"H-Hey Tadashi." Hiro rubbed the back of his shoulder nervously and looked at his older brother through his bangs.

Tadashi crossed his arms with an unimpressed expression.

Hiro could feel the waves of anger roll off Tadashi. He gave a toothy grin. "Happy April Fools' Day!"

To his surprise, Tadashi smiled but it morphed into something that looked forced and a little scary. Hiro started to back away from his brother, his hands held up in surrender and gesturing motions telling Tadashi to calm down.

Tadashi stared at Hiro, his eyes serious and his lips upturned in a smirk.

"Run."

AN – Posting this a day early because I'm out all day tomorrow -_- Massive thanks to my closest friend and sis, ForeverHalfa for helping me develop this idea! Truth be told, I'm not good at writing comedy, sorry if it seemed a little shaky. Hope you liked this oneshot and Happy April Fools' Day! If you could leave some feedback then that would be awesome. Thank you very much for reading! :)

(*1) In the film where Tadashi goes through all his tests, there's feedback after Baymax greets him.

(*2) If you ever burn yourself, don't ever peel back your clothes. This guy at my work accidentally spilt some hot water on himself and then immediately took off his shirt. Not a good idea.

(*3) This is my logic here. Baymax didn't float straight away when he was inflated because he was still in his charging station where he was still held down.