My Hero Academia: Rise of Ben 10, Book 1.

The Hypnotist Revealed

"Are you ready?" 

Echo Echo multiplied himself into three clones as Jiro's earphone jacks slid over to the center Echo Echo.

"We'll start off with only 2 more." said Jiro. "Any larger of a number and I don't even think Recovery Girl can get back whatever hearing loss our friends are about to suffer. You guys good over there?"

"WHAT!?" Izuku yelled, his ears stuffed with tissues. 

"I THINK SHE ASKED IF WE'RE GOOD!" Uraraka exclaimed, similarly with tissues in her ears.

"I HAVE NO INTENTION OF HUMPING WOOD!" exclaimed Izuku, looking disconcerted. 

"YOU WANT TO HUMP KAMUI WOODS!?" squealed Uraraka. 

"YOUR GRANDPA DID WHAT TO TIGER WOODS!?" Bakugou yelled.

"WHAT!? 

HUH!? 

OF COURSE!"

"WHAT ABOUT PIE!?"

"HUH!?"

"I think they'll be fine." said Echo Echo.

"Yep." said Jiro. "Let's do this. Earmuffs ON!"

Another Echo Echo clone jumped onto Kyoka's shoulders and covered her ears with his hands, as she was more sensitive to sound than the others being closer to the 'point of impact'

At the same time, the biomechanical wires on the center Echo Echo clone's earphone-like head amps, disconnected from the pack on his back, displaying similar plugs to earphone jack. Kyoka fitted her earphone jacks roughly into the plug holes. They were not an exact fit, but similar enough to do the job. 

It really was an odd coincidence that something as random as a Quirk was somehow roughly compatible with an alien species from millions of lightyears away. Or at least that was Kyoka's reasoning. It was almost as if she and Ben were meant to do this.

The center clone nodded. "Got it, let's get hooked up guys!"

Echo Echo's fingers retracted halfway as what appeared to be an assortment of plugs and outlets formed, and all the clones connected their fingers together. 

All The Echo Echos were capable of hooking up to each other to combine their sonic power into one massive amplified attack.  (not a canon ability, only available in ACSO and this series). And while it wasn't a largely viable ability in quick fights due to how long it took to set up, in this situation, it worked. Especially since Jiro discovered when Ben and her were experimenting with his abilities, that she had a rather deadly affinity with this alien. 

Her attacks worked by amplifying her heartbeat through her plugs, which could be turned into deadlier sonic attacks. 

However.

For some odd reason. 

When amplified through Echo Echo...

Kyoka gulped. "If I'm not careful, I'm gonna break bones. Ben! Extra precautions! Lets go!"

"Gotcha!" 

There were more flashes as multiple Echo Echos ran out and stacked on top of each other till they formed a defensive sound proof wall between them and Izuku, Bakugou and Uraraka. 

"Here we go!" Kyoka let loose a pulse into the center clone.

The center Echo Echo clone shook a little, as did the connected other two clones. 

They suddenly both inflated their cheeks and chests, as if they were balloons, barely keeping something contained.