She looks up at it with alarm.

It's nowhere near big enough for a person to get through.

The grille pops off.

A cat-sized mammal peers at her.

"Are you a witch's familiar or a 孵化器?"

I'm a 孵化器.

"Cool, neat. Are you here because of the witch?"

I'm here because of you.

Do you have a wish? What do you want most, with your whole heart?

Something's pounding on the bathroom door.

"I wish--right now I especially wish--that I could control witches!"

The cat-sized mammal leaps onto her chest, clinging to her collar with its forepaws, and touches her face with its ear-tendrils, and there is light.

She emerges in hanfu dress, black outer robe over red inner, her hair held up by a red stone comb carved into a nine-petaled lotus shape. A black lacquered dizi flute with a red tassel appears in her hands. She looks at the flute, then at the door, then raises the instrument to her lips and begins playing. 

The 孵化器 disappears back up into the air vent.

The startling glow of her gem, red and sun-bright, starts to drop.

What would she like this monster to do?

She would like it to RELEASE ALL ITS VICTIMS and COME TO HER LOCATION IMMEDIATELY. 

The banging on the door stops.

After a delay, the entrance to a witch-barrier, shimmering gold, slides into the bathroom through the hinge-side crack in the door, distorting to get between the hinges and then expanding again on the wall for her.

She stalks inside. She is still playing the flute, and orders the witch's familiars to not attack her and to lead her to the witch itself. 

The familiars - distorted versions of children's toys, here a rubber duck, there a teddy bear, one Barbie doll with even more outlandish proportions than normal - make way. A red wagon rolls into her path and turns to show her the way to the witch. The witch is a merry-go-round, jangling music that keeps trying to escape from matching Wei Ying's tune but can't, keeps trying to have the horses spin faster than the pace she sets but can't.

She doesn't have a weapon weapon other than her flute. 

So she uses teekay to beat the shit out of it with her busted cell phone. 

This takes a while. Her gem is dangerously low by the time the carousel lies in ruins at her feet between drifts of Legos on Candyland-board flooring, and then everything shivers, and vanishes.

She gets a seed for her trouble.

She offloads charge onto the seed. 

This makes her feel much better. It doesn't get her to the same brilliance she had to begin with, though, not even when it's full.

Concerning. 

She turns back to her normal clothes and pockets the seed and unlocks the bathroom door and peers outside. 

The medics are rushing around trying to triage people. Somebody on a stretcher being rushed past spots her and mouths "thank you".

She gives them a weak thumbs-up. 

Then she trudges to the bus stop and goes home.

"A-Ying!" Jiang Yanli says, concerned when her little sister comes through the door looking frazzled. "Are you okay?"

"...Ish? Uh. There was a monster at the hospital and there weren't any magical girls around so now I am a magical girl and it is dead." 

HUG. 

"Do you need some alone time? I can hold off A-Cheng..."

"No, let's get A-Cheng's overprotective wrath over with," she sighs. 

Predictably, A-Cheng is Not Amused by Wei Ying's story, and demands a lot more details than their older sister did. Madam Yu catches wind of it and spends about ten minutes yelling at Wei Ying for being reckless, after which she escapes to her room and gets on her computer. 

yingyingyingyingyingyingyingbananaphone: ok so it turns out showing up at places witches are known to have been without making sure someone took care of the witch is dangerous