Rainbow Dash flew upward, barely able to carry Rarity.
"Oh, Rainbow Dash, if it wasn't for me being such a show off, we wouldn't even be in this situation!" Rarity exclaimed, looking up at her pegasus friend.
"Rarity, it is fine," she paused, "I have an idea as to how we can get to the ground quicker."
With that, the pegasus flew downward, spinning in a circle, Rarity clutching on for dear life. Both gasped as a bright light surrounded them.
Up above, Twilight, Applejack, Pinkie Pie and Fluttershy could barely see what was happening.
"Is that the Sonic Rainboom?" Twilight asked, confused.
"It's not rainbow, is it?" Applejack deadpanned.
"I suppose so..." the unicorn murmured.
As the light faded, Rarity and Rainbow Dash had seemingly vanished. In their place fluttered a pegasus with a light blue coat, and a rainbow mane and tail with a purple tint, in a style much like one of Rarity's more tomboyish ones. They had heterochromic eyes, one the same blue as Rarity's and one the same magenta as Rainbow's.
"That's not a new pony!" Twilight realized. "That's both of them! As one!"
"I've never heard of somethin' like that happenin'!" Applejack exclaimed.
"Me neither, but I'd also never heard of the Elements of Harmony before Twilight told us about them," Fluttershy mused.
"That's so... hm... cloudtastic!" Pinkie exclaimed.
"Cloudtastic?" Fluttershy questioned.
"As in, "I gotta get up onto the clouds and yell to everypony how cloudtastic this is"!" Pinkie exclaimed.
Without a second of loss in her concentration, the Rarity-Rainbow Dash combo flew into a downward spin yet again, before quickly rocketing up.
A sonic boom and a rainbow combined, as Pinkie had described the Rainboom as earlier. The "fusion" paused to look at it, mid-flight, before rocketing back down to the ground.
Fluttershy carried Applejack down to the ground, while Twilight levitated herself down and Pinkie... well, she's Pinkie Pie, she got down somehow.
"That... was... AMAZING!" Pinkie exclaimed.
"The Rainboom or the fusion?" the fusion's voice was brash like Rainbow's, but elegant at the same time.
"Both!" Fluttershy exclaimed, running to hug her friend.
"Rainbow Dash, Rarity, can ya hear me, or are ya one now?" Applejack asked.
"Yes and no," the pegasus shrugged. "We can hear you separately, but we're also one... it's complicated."
"I've never heard of anything like this happening!" Twilight exclaimed. A bright light surrounded the combo, as Rainbow Dash and Rarity appeared where the "fusion" once was.
"Rainbow Dash, darling, that was incredible!" Rarity exclaimed, hugging her friend.
"It sure was Rares!" Rainbow exclaimed.
"What was it like while you were combined?" Fluttershy asked.
"Well..."
The blue eye of the combo squinted with worry as they flew in a spiral.
"Rarity, are you okay?" the combo's voice was more tomboyish, and clearly Rainbow was speaking.
"No... Rainbow Dash, darling, what if I can't do it in time? What if we..." they couldn't finish their sentence.
"I'll take charge, okay? We can act as one, but only if we're truly in sync and know what we're doing. Got it?"
There was a pause.
"Got it."
"We were still separate, yes, but when we were in harmony we acted as one being. Neither of us spoke, it was a whole new being speaking." Rarity explained.
Twilight was scribbling down on a piece of paper she had brought - it was meant to be used in order to write about the Rainboom, but the Rainbow-Rarity combo was more interesting.
"We also thought of a name for ourselves when we're combined," Rainbow said, "Rainbow Jewel."
Twilight nodded, scribbling that down.
"I wonder if we can all do that!" Pinkie exclaimed. She turned to Fluttershy, jumping on the pegasus and giving her a hug.
"Well if we can, it doesn't seem like hugs'll work. I'd bet a few bits we hafta be in sync and workin' towards the same goal, at least at first." Applejack butted in.
"I bet this is because of the Elements!" Pinkie jumped off of Fluttershy, who giggled a bit. "Rainbow Jewel was a literal Element of Harmony, if Applejack's right!"
"Pinkie Pie, you might be onto something!" Twilight exclaimed.
"I am?"
"She is?"
"Yes! Don't you see?!" the unicorn's eyes sparkled. "The Elements must have given us this ability! They're elements that are needed in friendship, and harmony is one of those! Rainbow and Rarity were in perfect sync when they combined, or in other words, perfect harmony! The Elements of Harmony, the harmony of friendship! It's all connected to harmony!"
"I think yer onto somethin'..." Applejack murmured.