Your neck and chest bulge outward as you breathe. Your belly yellows as your arms and legs grow darker green. Your legs seem longer, but you're having trouble standing, you are forced to bend your legs and squat on your belly. An insect buzzes nearby, and you instinctively open your mouth, and extend your tongue, but it's too short now to catch the flying creature.
"Heh, heh, good thing you didn't catch her, she's a lightning fairy. She would've shocked you good," cackles the witch.
"I'm turning into a frog? How is a frog supposed to warn anybody, let alone kill them?"
"It's a case of size matters, Kermit- nah, I call you that, they'll be calling me Miss Piggy. I know Ribbit, that'll be your name."
"Until I croak?" you ask nervously.
"Oh, a frog with a sense of humor, I like that! Don't worry, froggy boy, my friend the Mummy is sending a swarm of beetles to feed you. I expect you to be at least 500 lbs by the end of the day, and then you won't be eating bugs anymore, just the stray sheep or nosy human. Heh, heh!"
"Wait, the fairies let an evil witch live in their kingdom?" you ask in a confused tone.
"Not all fairies are goody-goody. Actually most really aren't, they just have a good propaganda agency, silly!" Then she added, "But if any of the goody-goody ones show up, you have my permission to eat them." She turns and walks through the closed gate without opening it.
You turn thinking to bolt now that she's gone.
"I wouldn't do that!" squeaks the lightning fairy that's still buzzing around. "I have orders to zap you if you leave the confines of the palace or the moat."
"You work for the witch? Why don't you guard the castle?"
"Too many fried humans," she explains sadly, "The witch said warn them first, but I always zap first and ask questions later. One was king coming to pay her tribute. Tribute got fried too, so now I'm reduced to backup and pet watching duty." Then realizing she hadn't introduced herself, "My name's Sparky- at least that's what that unimaginative witch calls me. You can call me Sparkle."
"Uh, you really can fry people? You're so tiny?"
"Oh, the witch's size matters thing? Well, she's right for intimidation size does matter. People are too ready to challenge a fairy, so even when I warned people they would swat at me, and I'd have to zap them." She motions toward the edge of the drawbridge. The moat is filled with charred skulls and bones. You swallow nervously. She adds with a shrug, "That weird looking one was the witch's last familiar, only partially transformed, he bolted like you were going to- and I bolted him or maybe it was a her?"
You have the urge to - "RIBBBIT!" You reach to adjust your boner, but it has been absorbed into your new cloaca.
The fairy laughs and flutters around you. "You are going to be a cute frog, tadpole."
"Tadpole?" you ask then you notice your tail. You're part frog and part tadpole. Damn, you're hungry. There is a buzzing sound in the east. You hop to face the approaching swarm and lick your ever widening lips.
"I better get clear before the feeding frenzy begins," said Sparkle moving back to the safety of a broad oak.
A man is running down the road toward the palace. He keeps looking over his shoulder. The swarm of scarab beettles blackens the road behind him. He stops at the end of the drawbridge and stares at you, unsure what to do. The swarm of black beetles envelope him. He gasps, and his now fleshless skull falls forward out of the moving mass of insects. Your tongue is flying, crunch crunch crunch. Just like popcorn, or potato chips, you devour the swarm hungrily as your tail is absorbed into your growing bull frog body.