Firstly, this episode could probably be set any time in the second season. Or the first for that matter, it's only spoiler is for Witch.
Secondly: The following story is intended for entertainment purposes only. This document can be freely distributed with the condition that no part of the text is modified, and this notice is included with all copies.
Some characters and elements of this story are the property of Joss Whedon and
Mutant Enemy and are used without authorization. No copyright infringement is
intended. The author receives no compensation from the distribution of this
work. Any comments or criticism would be welcome.

"Hey Buff. How're you passing the time til our exciting chem class?" Xander marched into the library.
"I'm trying to think of demons that could rise and cause me to skip class," replied Buffy lazily.
"Oooo, do I detect a note of boredom?" grinned Xander.
"Absolute boredom. To the extent that sitting in the library with Giles seems interesting."
"Where is the book-man anyway?" asked Xander, glancing round.
"Some meeting," yawned Buffy. "I can't believe I'm in here and he's not. It must be prophecy missage."
"Oh, sure. It's all the hero stuff isn't it. Makes you look good," grinned Xander. "Y'know, I used to have things under control."
"You did, huh?" Buffy raised an eyebrow suspiciously.
"I've lived on the Hellmouth all my life," Xander tried to defend himself. "And in the same town as Cordelia."
"That's true," conceded Buffy. "I stand in awe."
"And so you should, lesser hero."
Buffy smiled. "Where's Willow?"
"Probably vanished into thin air," suggested Xander. "As she does at times of." Xander grinned as he remembered a long forgotten incident, which up until now he had simply dismissed as impossible.
"Xander?" Buffy tried to bring him back to the point.
"Y'know she actually did that once. Well, maybe anyway."
"What?"
"Vanished into thin air," replied Xander.
"Willow vanished into thin air?" Buffy looked sceptical. "I know this is the Hellmouth, but. I'm going to regret asking this, aren't I?"
"No." Xander looked hurt. "This is a perfectly good story."
"Go, go. Anything to avoid another minute with my thoughts."
"It was the night Willow's parents were away overnight for the first time. They'd spent weeks worrying about it, making sure I could come over even though I was always there anyway. We were about 13.
Me and Will were both really excited, suddenly we had free run of the house all night. It was a great prospect. Lots of food, her Mum and Dad didn't want us to go hungry, games, vids. It was heaven.
We even discovered a huge tub of choc chip. Sorry, I know, I know, the story. OK, well Amy came round. Will said she looked really upset, like something terrible had happened, but I couldn't see her. I just heard her. She said her Mum thought it was unfair for Willow to make her all those brownies and get nothing in return. So as Amy and her Mum drove off, Willow came back in shouting to me that we'd been given even more food. Free brownies, what a night."
". I thought Amy's Mum was really against anything remotely unhealthy," interrupted Buffy.
"Hey! Did you want to hear this story or not? I'm gettin' to that bit," protested Xander.
"Sorry, go ahead."
"When I got to the door, Willow had vanished. Literally, she'd gone. It was really wiggy."
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Xander stared at the box of brownies which he had been so excited about moments ago. They looked so tempting, really tempting, but he was worried about Willow. She had been there a second ago, and now there was just a pile of broken brownies in a box, one of which had a bite taken out of it.
"Willow? Willow!" Xander ran through the entire house, and even searched the yard for his friend. She had literally vanished.
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"Wait, Xand. You didn't eat any of the brownies? That's of the strange," commented Buffy.
"Hey. My bud was missing. I can't help being hungry sometimes, I'm a growing man, but this was an emergency." Xander frowned at Buffy.
"Sorry, Xand." Buffy patted him on the back, hoping he didn't get any more agitated.
"So I was looking for Willow, without eating."
***************************************
Xander began to feel frantic. What if Willow was really badly hurt and that was why she hadn't answered his calls? He raced through the house more thoroughly, stumbling up the stairs. He couldn't help but begin to imagine what Willow's parents would say. How he'd let them down, and Willow. They'd only been gone for half an hour and already he'd failed.
As he returned to the area by the front door, Xander tripped and fell, landing sprawled out on the floor. He groaned. Dusting himself off, he staggered back to his feet, only then realising that it was the brownies that he'd fallen over. And they too had vanished. All that remained was the box, and a note in Amy's careful handwriting.
Willow
Don't eat the brownies! My Mum caught me, and she wasn't pleased. If you eat them you will get turned into a fly (severe diet!), although I think it wears off after a while.
I'm really sorry
Amy
"Oh God," cried Xander. "A fly? She has to be kidding. People can't do stuff like that, right Will? Oh, Willow. You're supposed to tell me what to do!" Xander pulled himself together. "OK, so Willow's a fly, but it'll probably wear off, so she'll be all right." Xander relaxed slightly. "Except if I fell on her!" He instantly began a thorough inspection of his clothes for any sign of a squashed fly. They were clean. "Phew, had me worried there for a minute, Will." Xander shook his head.
"What if someone else gets her? A spider?! I gotta find her. But how? How do I attract a Willow-fly?" Xander sank to the ground, carefully checking that he wasn't sitting on any flies first. His brow furrowed as he concentrated, trying to work out what to do.
His train of thought was interrupted by the telephone.
"Hello?"
"Hi Xander. Can I speak to Willow, please? It's her Mum."
"Err."
"Xander? Is something wrong? Is Willow OK? I'm coming back right now!"
"No! No, err, Willow's fine. She's just, err, in the bathroom. Yes, doing bathroomy things. She'll be fine."
"Are you sure everything's OK?"
"Yes, yes, fine. Everything's of the good, err, fine."
"Xander, what are you hiding?"
".Well, OK. Willow ate too much ice cream." Xander crossed his fingers as he lied to Willow's Mum. He could almost feel her relief.
"Oh, right. Well you tell her to take it easy with the rest of it then, Xander."
"Oh, sure. I can help out, no problem," grinned Xander.
"OK then. Get her to call me back when she feels better."
"OK, bye."
"Bye, Xander."
Xander sagged against the wall in relief. "That was too close," he sighed. "I'm gonna kill Amy." Getting his brain back in gear, he returned to the problem of saving Willow. "Wait! I have an idea! Oooo, a plan." Xander rubbed his hands together in glee and raced into the kitchen to rummage through the cupboards."
"Come on, come on. You gotta have some somewhere," cried Xander as he searched. "Yes!" He grabbed a jar of honey and ran through the front door onto the porch. Quickly, he spilled some honey on the flags outside the house, and sat and waited for a fly to arrive and get stuck.
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". It only took a couple of minutes, and there it was, a little fly. I am the man of ideas! Bow down before me!" Xander did a little dance, smiling at the memory. "Only then this guy came up and attacked me."
"Vampire?" asked Buffy.
"Look, vampires weren't real then. I can't go back and post-date, well. probably. He looked pretty weird, but I didn't really think about it. I was distracted OK, it's not every day your best bud gets turned into a fly by her friend's Mum. Even on the Hellmouth!"
" 'K. So, the probably vampire. No slayer.?" encouraged Buffy.
"Well, I fought him off, no problem."
Buffy raised an eyebrow.
"OK, OK. Some other guy came and fought him and I ran off. Happy?"
"Reassured," replied Buffy.
"Ah, the slayer doesn't like competition. Sorry." Xander looked sheepish. "So, I, Xander-the-Great dived back to the porch to see how the fly was doing and if it'd turned back into my best bud, when I realised that the fly was in danger of extinction because this frog had detected lunch."
"Oh God," said Buffy.
"So I reached out to grab this frog, about to teach it a lesson it'd never forget, when I discovered that it'd already eaten the fly, and - OW." Xander rubbed his arm where Buffy had just hit him. "What was that for?"
"Making me think that fly was Willow," complained Buffy. "No fair."
"No fair?!" Xander began.
"Me?" asked Willow. "A fly? Xander.?"
"It was just a story, Will. Nothing to worry about. See? We're not at all worried. In fact we're so unworried that."
"Xander. You're babbling," observed Willow suspiciously. She turned to Buffy. "A fly?"
"Xander says you got turned into a fly by Amy's freaky Mum," stated Buffy.
"Thanks, Buff," groaned Xander.
"But, but. You said it was just a dream." began Willow. "You said getting turned into a fly wasn't possible."
"If you recall, Will. That was before I met Buffy here, and all her scary friends. Also, before I was aware that Amy's Mum could do the witch thing?"
"True, but. A fly? Why did you say it was a dream? You were there, you knew." Willow looked Xander firmly in the eye.
"Buffy, this is so not what I wanted," complained Xander. He turned back to Willow. "I didn't think you wanted to know." he began. "And besides, sometimes my poor stupid brain makes stuff up."
"Like this?" asked Willow.
"Admittedly, you having the same dream seemed unlikely."
"Guys! Before we get reminiscing, do you think you could fill me in? Where was Willow?" insisted Buffy.
"Right. Well." Xander paused to glance at Willow.
"Go. I think I wanna know too." Willow looked nervous. "Quick, before I change my mind."
"You could say the frog developed indigestion," grinned Xander. "You grew right out of its mouth, Will."
"W-was the frog OK?"
"Will, it had a 5ft human being growing out of his mouth."
"Oh," said Willow. "Oh dear."
"I thought you didn't like frogs, Will?" asked Buffy.
"I-I don't. But I don't wanna kill anything. That's like. killing. Is bad."
"OK, agreed, but it did eat you," pointed out Buffy.
"That's true," conceded Willow, more hopefully.
"So, what was it like, Will? Being a fly?" asked Buffy. "Do you remember?"
"Well, uh, yes," admitted Willow.
"You do? Oh, Will. Why didn't you say?" sighed Xander.
"You said I dreamt it."
"I'm sorry, Will. I didn't realise."
"It's OK, really. It's probably, uh, better I didn't know I was really eaten. by a frog." Willow shuddered at the thought. "Ugh, frogs."
"Come on, Will. Back to reality, huh?" nudged Xander.
"Oh, OK. Being a fly was quite good though, uh, except for that part with the."
". Focus, Will," interrupted Buffy.
"Right, good. But I can't.. being a fly. Was that really real? It was fun flying round and everything, but it was the hugest frog I ever saw. Bad frog, and it ate me."
"It was a bad frog, Will," agreed Xander, putting his arm round her. "But it's gone now. I'll have you know I even confronted Amy about it at school, and I was damn scary. She ran away." Xander looked proud.
"But it was real. I was eaten by a frog. I'm gonna have nightmares forever."
"Shh," whispered Xander, trying to comfort her. "You won, Will. The frog can't get you."
"Not that one, but what about the others? They could. What if the other dreams were really real?"
"Will." started Xander.
"I wonder if the guy who stopped the vampire was Angel," mused Buffy, intentionally distracting her friends.
The other two stared at her.
"Well it could have been," she edged.
"I don't believe you just said that," replied Xander. "In fact, I'm gonna pretend you didn't."
"I'm not sure I can do this," whispered Willow. "The world is full of frogs, a-and tadpoles. They know me now, and how I, uh, killed one of their kind. They're gonna be after me. They're gonna come and get me in my sleep, and."
"Will. They really didn't mind," smiled Xander, squeezing her shoulders. "And besides, you're with me. I am the frog-killer. Let all frogs fear me, for I will strike, err, fear into their hearts, or toes, or wherever it is frogs keep their scared bits, and they will never come near me. Or you," added Xander.
"Are you sure?"
"Come on, Will. Class calls." Xander grabbed her arm and started to drag her out of the library. "Very quietly anyway," he added. "I promise I'll fight off any frogs we meet on the way."
"Oh, OK," agreed Willow, then reconsidered. "Maybe we should bring Buffy?"
"Bye, guys," called Buffy.
"Or not," suggested Xander. "Frogs I can handle, Will. Behold Xander the Frog Slayer."
Willow giggled.
"And you can be watcher, if you ask nice."
"Yeah, coz I can research stuff. A-and I have inside knowledge." nodded Willow.
"See? They'll never defeat us," grinned Xander.
Willow smiled back. "In every generation there is a Chosen One. He
alone will stand against the frogs, the tadpoles and the forces of
amphibiousness. He is the Frog-Slayer."