Stab.

The child-thing seems to be on its last, uh, arms.  It's crawling towards her, breathing heavily.

She keeps half an eye on the rest of the rats and goes to stab that, too.

When the blade pierces it it screams and thrashes, and then explodes into wispy threads of spidersilk like the rats did.

The Barrier shimmers out of existence around her; the rats go with it.  She's back at the gazebo.

Kyubey is waiting for her there.  Kaylee is there too, sitting on the ground, curled up into a ball.

She sheathes the sword, vanishing it, and runs up to Kaylee. She hovers awkwardly next to her, unsure whether Kaylee wants a hug. (It's probably very obvious she needs a hug.) "Are you - are you okay? Kaylee?"

She's crying.  She shakes her head.

...She goes to hug her. She might be starting to shake, too, as the adrenaline fades.

Kaylee hugs her back.  She clings, a little.

After a while, she settles down - not crying, but still trembling a bit.

"I don't know why I..." she gestures weakly toward where the portal was.

The cat-creature approaches, slowly, and nuzzles Kaylee on the cheek, rather like an ordinary cat would.

"You were probably affected by a Witch's Kiss," it says softly.  "It can make you do things you wouldn't normally do, if you're not a magical girl."

"What was that thing?"

"It's called a witch.  They're the opposite of magical girls.  Magical girls are born from wishes and made of hope; witches are born from curses, and made of despair."

"That's - not an answer. Where do they come from, how did it control Kaylee like that - " She twitches and notices that she's probably still bleeding. She focuses on closing the wounds for a moment. This - is extremely freaky, and now that there's nothing to fight that's all she has to focus on. "And what are you, what am I - what are these powers?"

"Witches can control humans using something called a Witch's Kiss.  They usually make those humans try to hurt themselves or each other, since they're creatures of despair; sometimes they draw them into their Barriers to torment them instead.  It was sheer luck that the witch got Kaylee but not you.  Your wish healed her physically and magically, so she doesn't have the Witch's Kiss any more.  It would have been removed when you killed it even if your wish hadn't done the trick."

"My name is Kyubey; I'm a sort of magical creature whose job it is to create and guide new magical girls, and help you learn to fight witches.  You're a magical girl now.  You have the powers of any magical girl - you're stronger and faster than a human, you can conjure a weapon, and you have a few other talents."

She hugs Kaylee tighter. "What other talents? Like the healing?"

"Healing, yes.  Some magical girls can move objects with their minds.  You can create more than one weapon at once, and with practice and experience, modify them and control them even when you're not touching them.  Beyond that, it varies from person to person."

This is - too much. "How do I know if there's another witch around?"

"As a magical girl, you'll be able to sense them, and dowse for them.  If you're not sure, a sudden crime wave or increase in the suicide rate is a decent sign that there might be a witch nearby.  They aren't common, though.  There isn't too much risk you'll be attacked by another one very soon."

Kyubey turns to address Kaylee.  "You'll be safer if you're a magical girl, though."

"I will?"

Squeeze. "How's that? And - will you be sticking around to answer more questions later?" 

"Witches don't target magical girls, because Witch's Kisses don't work on them.  And you can contact me whenever you want.  I turned you into a magical girl, which means you're my responsibility.  You can talk to me telepathically as easily as you can heal yourself."

"Does - the magic cost anything?"

"It does.  Now that you're a magical girl, you have an object called a Soul Gem.  Using magic harms your Soul Gem, but you can heal it by displacing that harm into Grief Seeds, which you can obtain by destroying witches.  A Grief Seed that's used too much, or left alone for too long, will grow into a new witch, but Grief Seeds are the only way to heal Soul Gems, so you shouldn't destroy them right away.  I can warn you when a Grief Seed is near enough to used up that its safer to destroy it, and I can also destroy them for you."

"Did that - witch - drop a grief seed then?" She should probably get it if it did. "And what happens if I run out of magic?" (And she focuses, trying to sense her soul gem - it's on a necklace, resting at the base of her throat.)

"Yes, all witches drop Grief Seeds.  Using up magic harms your Soul Gem.  If your Soul Gem is destroyed, you die."

- Yikes.

She reluctantly unhugs Kaylee. "I need to go find that - Grief Seed thing." She'll start looking around. "Kyubey, what does it look like?"