H₂Orse: Just Add Water

by VitalSpark

Rating: everyone
Tags: Random, Crossover, Alternate Universe, Main 6, My Little Pony: Friendship is Magic, Rainbow Dash, Fluttershy, Adventure, Flash Sentry, Twilight Sparkle
Length: 3318

Twilight, Fluttershy, and Dashie become mermares for very little reason. Also Flash Sentry is randomly a rich kid that nopony likes.

This is a crossover between My Little Pony: Friendship is Magic and H₂O: Just Add Water.

Twilight Sparkle, Fluttershy, and Rainbow Dash are swimming in the pool on Knacker Island under a full moon, and become mermares. They're not all necessarily very happy about it.

Also Flash Sentry is randomly a rich kid that nopony likes.

Warning: this story would be tagged [Random] [Comedy] if it had turned out to be funnier. It's kind of a silly parody crossover thing. If you want a sensible crossover between H₂O and My Little Pony, try H2O: Just Add Friendship by Jaded Naruko (or just stop wanting that).

Cover is based on art by tashiepie and toonham. Pre-read and made slightly less awful by Remedyfortheheart and Infinity Shade. ♥Thanks♥!

Published 2015-06-07 19:10:01 UTC
Last updated 2015-06-07 19:10:01 UTC

Metamorphosis

Rainbow Dash swum through the water like a fish, kicking her legs and using her wings for extra propulsion. She reached the end of the pool and stopped. She looked up, treading water. "How'd I do?"

Fluttershy looked at her stopwatch. "Three minutes, forty point six seconds."

Rainbow hoof-pumped. "Awesome! That's point two seconds faster than my personal best."

"Yay!" Fluttershy whispered.

"You were like a speed boat out there," Rarity, who had been watching Rainbow practice, said. All the mares nodded and mumbled their agreements.

"But I can do better." Rainbow was brimming with confidence, as usual. "Just give me two weeks, and I'll be ready to win the Equestria Games."

Applejack knew what it was like to set unrealistic goals in competitive events, and didn't want her friend to suffer with shame like she had. "However you do, I'm sure you'll make everypony in Ponyville real proud!"

Rainbow dove back underwater and started swimming towards the other end of the pool.

♒

Celestia's sun was beating down on the pier mercilessly. Fluttershy wiped her brow with a hoof and took a sip of water from her bottle. Flash Sentry looked up from the boat he was working on. "Fluttershy! Hey, Fluttershy! I'm having some trouble here, can you help?"

Fluttershy looked at him. "I-- I don't think so."

"Come on… please! The good ship Shimmer won't go. All I need is for somepony to pass me some tools."

Fluttershy nervously approached Flash. "I'm not good with boats. Or goats."

"You'll be fine," the stallion said, downing his tools. "It took me a while to realise that someone's taken the spondoolit."

Fluttershy was confused by the technical terms Flash was throwing around. "The spondoolit? So will the boat work without one?"

Flash stood up, wiping his hooves on a rag. "No. No spondoolit means no magic, means no power for the boat. I was getting sick of this thing anyway."

"Why me? I didn't steal your spondoolit."

Flash shrugged. "Because you're here, Fluttershy. My dad can buy me another boat any time he wants. I tell you what, if you can get this one working, you can keep it." He laughed.

Fluttershy got the impression that Flash was teasing her. "That isn't funny."

"Are you kidding? Seems pretty funny to me, right, Thunderlane?" The two stallions laughed. Because Thunderlane was there.

Fluttershy's ears drooped and tears brimmed in her eyes. "This… Th-This isn't happening," Fluttershy said to herself.

Twilight walked over to see what was going on. She nudged Fluttershy and showed her the spondoolit she had hidden in her hoof. "You took that?" Fluttershy whispered.

Twilight responded in a hushed tone. "Flash Sentry's a pig! Anything I can do to get under his fur can't be a bad thing, can it?"

"OK, thanks Twilight." Twilight passed the spondoolit to Fluttershy. Fluttershy took the magical device and inserted it into the slot in the boat's engine. The engine sprang to life. "So the boat's mine now, right? I mean, if that's OK with you…"

The stallion's jaw dropped open. "Wha—?"

Fluttershy got onto the boat. "Yeah." Twilight got onto the boat with her. Fluttershy turned to her other friend, who happened to be walking past. "Hey, Rainbow, want a ride?"

Rainbow approached them sceptically. "Have you got a licence?"

Twilight answered sarcastically, as she did from time to time. "Are you her mother?"

♒

Soon the three mares were motoring along on the Shimmer. "Let's go out to sea!" Twilight suggested, grabbing the wheel and turning the boat away from the shore.

Rainbow Dash was wary. "Isn't that dangerous in such a little boat like this?"

"Chill out!" Twilight shouted as the engine started spluttering.

With a groan and clunk the engine came to a stop. Fluttershy started hyperventilating.

Rainbow face-hoofed. "Is this chilled out enough for you?"

Twilight was relaxed about the matter. "So what? It's not like we're sinking."

"Not yet," Rainbow said.

"I think we're out of fuel," Twilight said, stating the obvious. "Hey, why don't we paddle to that island?"

Rainbow Dash shook her head. "Knacker Island? Forget it!"

Fluttershy explained, "nopony goes there — it's surrounded by sirens and sea serpents."

Twilight shrugged. "Well, I can't see any there now. Besides, it's all we've got."

"Err… girls? Don't we all have wings?" Fluttershy asked.

"Of course you do," Pinkie Pie interrupted, springing out of nowhere even though she wasn't even in this scene, "but for the purposes of this narrative, we have to ignore them. Otherwise the entire story falls apart." She disappeared back to wherever she'd come from.

♒

As the sun set, the three mares secured the boat to some rocks with a length of rope.

Fluttershy looked up and down the small beach they'd landed on. "How will we ever get back home?"

"Good question, Fluttershy," Rainbow Dash said. "Ask Princess Smarty-Pants."

Twilight looked cross. "Don't pin this one on me!"

Rainbow Dash's response was dripping with sarcasm. "Oh, it was somepony else's fault? I suppose somepony else took this thing miles off shore?!" She took out a magical communications device. "You two are lucky I've got this!"

Fluttershy smiled. "Rainbow's always prepared."

"Oh, I'm so happy for her," Twilight said, eliciting a dirty look from Rainbow Dash. Though in truth, Twilight was genuinely relieved.

"Urgh! There's no magical signal here on the beach." Rainbow tapped at the device with her hoof. "We need to get to higher ground."

♒

The mares walked through the jungle, up a steep slope, just as the last light from Celestia's sun was fading.

Twilight tripped on a root and stumbled, but managed to regain her balance. "Do you have any idea where we're going?"

"Just… up!" Rainbow held her communication device in front of her, inspecting its screen. "Still no magical signal."

"Maybe we'll never get a magical signal, and then we'll never communicate with Ponyville, and nopony will find us… then what?!" Fluttershy was always the voice of optimism.

Twilight shrugged. "Then we'll draw straws and decide which pony the others will eat."

Rainbow looked sternly at her, knowing how much Fluttershy tended to worry about things. "That's not funny."

"I'm relieving the tension, Fluttershy."

Fluttershy shook her head. "You're making it worse."

"Come on!" Rainbow pressed on up the next bit of hill. "Watch your step."

Fluttershy tried to catch up with the blue pegasus. "I can't — it's too slippery." She ruffled her wings. "There has to be another wa--" Fluttershy fell down a slope, sliding through vines and mud and landing on her flank at the bottom.

Rainbow Dash and Twilight lost sight of her. "Fluttershy? Fluttershy?!"

A voice came up from the ravine. "I'm OK. I'm fine."

Rainbow peered into the dark crevice. "Can you climb back up here?"

"I don't think… no," came the voice.

Twilight was impatient. "Are you sure? Can't you at least try?"

The voice again. "I can't — it's too steep and slippery. There's no way I can climb up."

Rainbow looked at the slope. It didn't look too hard for her to handle. "I've got to get down there!"

Twilight looked at Rainbow Dash like she was out of her mind. "Are you crazy?! Then you'll both be--"

Rainbow Dash screamed. Twilight looked over to see that Rainbow Dash had been trying to climb down to reach Fluttershy but had slipped and fallen herself.

Rainbow was now at the bottom of the ravine with Fluttershy. "Are you OK?"

Fluttershy rubbed her back hoof. "It hurts a little here."

"It's probably just sprained."

"Whee!!!" Rainbow Dash and Fluttershy looked up to see Twilight careering down the slope like a foal on a playground slide.

Rainbow shouted at her. "Just what in the name of Celestia do you think you're doing?!"

"Well, you came down," Twilight answered.

"You were meant to stay up there and throw us a rope!"

Twilight took a defensive pose. "Do you think I'm some kind of telepath?! Like I've got freaky mind-reading skills? Besides which… what rope?"

Fluttershy interrupted. "Can we please stop arguing and just concentrate on getting out of this ditch?"

Rainbow Dash nodded. "Yep." She tapped her communications device. "It's no use. It must have been damaged in the fall." She threw it onto the ground.

Twilight looked around. "There's no way out."

Rainbow pointed a hoof to an area that seemed a little further down hill. A small stream near their hooves seemed to be trickling in that direction. "Let's try this way."

The mares wandered a little way until they came to an almost perfectly round pool of water, surrounded by a beach of black sand. Further away from the pool, the beach was surrounded on all sides by a cliff. There didn't seem to be any way up. Twilight ran her hoof through the sand. "Wow! Is this a volcano?"

Fluttershy squealed. "It's… umm… not going to erupt, is it?"

Rainbow stated authoritatively, "the Knacker volcano has been dormant for a thousand years. I think we're safe." She noticed rings around the beach. "Look! Tidal rings!"

Twilight looked at her blankly. "So what?"

"It means that this pool is connected to the ocean. There might be a way out!"

Fluttershy looked worried. "I'm not going to like this, am I?"

♒

"Rainbow? Rainbow?!" Fluttershy called, staring at the black surface of the water.

"Relax — give her time," Twilight said.

Rainbow Dash's head splashed out of the water, her wet mane framing her face, the colours of her hair muted in the dim light. Ripples broke up the reflection of the full moon in the surface of the pool. She shook her head, and her mane was restored to its usual style. "I was right. It's about a twenty second swim to the beach. There's plenty of room — we can all fit."

Fluttershy backed away from the pool. "Through there?! No way! I can't do it! I can't swim!"

Rainbow came out of the water and put her hoof around her friend. "Come on, Fluttershy, there's no other way out. You can do it."

"Everything will be fine," Twilight said.

"But how can you be sure?" the nervous yellow mare asked.

Twilight attempted to reassure her. "Listen to Rainbow, Fluttershy. When has she ever let you down? Besides, what's the alternative? Are we supposed to stay here for ever, ever, ever, ever?"

The surface of the water started rising. Fluttershy marvelled at it. "Wow!"

"Spooky," Rainbow Dash said. The three mares stepped into the water. "OK… now take a deep breath."

♒

The three mares' heads burst out of the water.

Fluttershy looked angrily at Rainbow Dash. "That was a lot more than twenty seconds!!"

Twilight patted her on the back. "Relax, we made it, didn't we?"

Rainbow smiled at Fluttershy. "I knew you could do it! I'm so proud of you, Fluttershy!"

Fluttershy's initial anger dissolved and she smiled at her oldest friend.

A voice boomed out of nowhere, and spotlights lit the water around them. "Royal coast guard! This is the royal coast guard! Please swim to the ladder at the rear of the vessel."

Rainbow pointed towards a ship. "Come on!"

♒

The next day Rarity was knocking on Fluttershy's front door. "Come on, Fluttershy, you can't stay in there forever. Our appointment at the spa is in ten minutes — we'll never get there in time. You know how Aloe can get when she's kept waiting — it's not pretty."

Fluttershy looked at her tail. There was no way she could answer the door looking like this.

♒

Rainbow Dash arrived at the pool early for training. She always loved to get there really early, when she was the only pony there — it was like she had a whole private pool just for herself.

She dived into the pool, swum a few strokes and then stopped, treading water. She dipped her head under the surface for a moment to look at her tail.

"Whoa!"

♒

Twilight walked alone through the castle gardens. Suddenly the sprinklers turned on to water the grass — they were on an automatic timer. The droplets splashed Twilight and suddenly an amazing transformation occurred. Her back legs disappeared and her flank and tail turned into a purple fish tail.

"Whoa!"

♒

Twilight Sparkle, Rainbow Dash, and Fluttershy were gathered at Fluttershy's cottage.

Fluttershy continued explaining: "… it was pink, and covered with scales!"

Twilight interrupted. "It happened the minute the water from the sprinklers hit me!"

Fluttershy was panicking. "I was a fish!"

Rainbow was confused. "What's going on with us?!"

"Yes, that's what I want to know," Twilight said, flicking through the pages of a book she'd brought with her. "Have you told anypony else?"

Fluttershy shook her head. "No, I was supposed to be going to the spa with Rarity. She turned up here, and I refused to open the door."

"What's happening to us?" Rainbow asked.

Twilight sighed, putting down the book which seemed to offer no answers. She splashed her flank with water, waited a moment, and sprung a fish tail. "About ten seconds after we touch water, we grow these." She gestured at her tail.

"And it vanishes when I'm dry again," Fluttershy said. "That's the same for you, right?" The other mares nodded. Twilight's tail was already beginning to transform back. "The tails are like…"

Rainbow interrupted, "… exactly like…"

Twilight completed their thoughts. "We look like mermares!"

Rainbow shook her head. "I told you before, that's not funny! Mermares don't exist!"

There was a knock at the door. Fluttershy looked at her companions. "Oh no! That's Pinkie! I totally forgot she was bringing Gummy here for his check-up today!"

Pinkie's excited voice came from outside. "Fluttershy! I'm here! Or did I get the time wrong?"

Fluttershy opened the door a crack. "No, I said ten o'clock. But, sorry, we're a little busy."

Pinkie pushed the door aside and bounced into the room. "Come up? What's come up? Are you girls having a party?"

Fluttershy shook her head. "Oh, no, no, no, no, no… just something important." Then she remembered how keen Pinkie always was to help her friends. "Not so important that you need to worry about it, but sorry, Pinkie, I have to cancel."

Pinkie was disappointed. "Oh, maybe some other time."

"Pinkie, you're smart — do you know anything about mermares?" Fluttershy asked as she was showing Pinkie out.

"No, not really."

"Oh, OK, sorry, bye." Fluttershy shut the door and turned back to see her two companions staring at her.

"Do you know anything about mermares?" Twilight asked, doing her best impression of Fluttershy's voice. "Are you crazy?! You know how intuitive Pinkie is — she'll guess!"

"Fluttershy," Rainbow said, "we need to take this seriously. We don't know what this strange thing is that is happening to us. How has it happened? And why?"

"We need to find out more," Twilight stated.

"But how?" Fluttershy asked.

"We need to get back in the water," Twilight answered.

Fluttershy shook her head. "No way. I am not getting back into the water."

"In the interest of science," Twilight said, "I'll go. But I don't think I should do it by myself. Any volunteers?"

♒

Rainbow Dash and Twilight Sparkle were standing on a secluded part of the beach.

Rainbow approached the water nervously. "I'm still not so sure about this."

Twilight strode towards the sea. "That's OK — I am."

"That gives me no reassurance whatsoever."

Twilight stepped into the water and the waves lapped at her hooves. "About ten seconds, right?"

The mares both started counting. "One, two, three, four, five…"

Twilight wailed as her back legs disappeared and were replaced by a fish tail.

♒

Fluttershy walked into Sugarcube Corner and saw Pinkie Pie bent over a book. "Pinkie, what are you doing?"

Pinkie looked up from her reading. "Well, you asked about mermares, so I thought I'd look through some of Nana Pinkie's books on Equestrian legends."

"That's really nice of you, but you didn't need to do that."

Pinkie closed the book. "I know, but I've got way too much time on my hooves. Anyway, I found out some really good stuff." Fluttershy looked at her expectantly, and Pinkie continued. "Mermare myths have been around since the time of the three tribes…"

"Did ancient ponies really believe in that stuff?" Fluttershy interrupted.

"Sure! Sometimes they were good omens, but sometimes they brought trouble."

"What kind of trouble?" Fluttershy asked. "Sometimes trouble can be really troubling." The bell attached to the door rang as a customer came in — Flash Sentry. "Oh no, here's some trouble."

"Just ignore him," Pinkie Pie cautioned. "Oh no, he's coming over."

"What do you want, Flash?" the yellow pegasus asked.

"My father didn't appreciate having the royal coast guard knocking on his door in the middle of the night," Flash said with a hint of anger.

"Well you shouldn't have said that I could keep the Shimmer," Fluttershy suggested.

"I don't like ponies making me look bad, Fluttershy," Flash said, "especially fillies like you."

"Sounds like you're scared of your dad, Flash," Pinkie said, leaping to Fluttershy's defence.

Flash Sentry squared up to Pinkie Pie. "You think you're better than me, Pinkie, is that it?"

"Everypony's better than you, Flash," Pinkie answered dismissively, "if you haven't learnt to live with that fact by now, then there's no help I can give you."

"Tough mare, huh?" Flash said to Pinkie. He turned to address Fluttershy. "Got yourself a protector, have you, Fluttershy? It's not going to do you any good. You know, one of these days, with or without Pinkie…" he muttered as he walked away.

♒

The three mares were in Twilight's throne room discussing what they'd discovered so far. Rainbow was recounting to Fluttershy what she and Twilight had discovered at the beach. "… So we came out of the water, and once we were dry, everything went back to normal like nothing had ever happened!"

"But it did," Twilight said, "Squee! This is the best experience of my life! First: wings! Now: a tail! I mean, I've always had a tail, but not like this! It's so exciting!"

"Calm down, egghead." Rainbow passed Twilight a glass of water. The princess took a sip and regained her composure. She put the glass down. Rainbow huffed. "I don't think it's so brilliant. How am I going to compete in the Equestria Games now? Everypony will see! I can't--"

Fluttershy uncharacteristically interrupted. "Did you see that?" She pointed a hoof at Twilight's glass of water, which was now miraculously full. She held a hoof over the glass, and it started to fill even more. "Look, it's starting to spill over now."

"That's just not scientifically possible," Twilight said, "You're not scientifically possible. Where's all that water coming from?"

"I don't know," Fluttershy answered.

Rainbow looked at the glass. She held her hoof above it too, and again water started to spill out of it. "Did I do that?"

"It wasn't me," Fluttershy said.

Twilight announced, "this… is… awesome!"

Rainbow was confused. "But all I did was…" She held her hoof over the glass, and again it started to overflow.

"OK," Twilight laughed, "why don't I get to do cool stuff like that?"

"This isn't funny," Rainbow said, "we've got to keep this a secret from everypony so we don't end up being studied and dissected by some secret royal institute."

Twilight scoffed. "Princess Celestia would never do that!"

"All the same," Rainbow cautioned.

Fluttershy looked at her friends, "so this secret is just between the three of us, right? We're not going to tell Rarity, Applejack, and Pinkie?"

Rainbow nodded. "Our secret. Whatever happens, we're in this together."

"That doesn't mean we're married does it?" Twilight asked.

Rainbow laughed. "Now that actually was funny."

Author's Note

Sorry. Please don't hit me!