As Rainbow Dash climbed, she realized she was falling. Or, perhaps, she was doing neither. Whatever the case, as she spiraled through the kaleidoscopic expanse of clouds and continents, the colors and shadows around her began to bend. An undulating motion filled the limitless expanse of Cider Space, and she heard a great rumbling from a distance.
Curious, the pegasus hovered to a stop, slowly twirling one thousand and eighty degrees. As Epcot twirled around her, she bent around and stared towards a rippling source of light. At first, she thought that maybe her eyes were crossing—until she reminded herself that she wasn't even using her real eyes. Entire shelves of the sky were cascading towards her, one atmosphere at a time, like giant translucent dominoes. Through the spaces between each shuffling slice of the universe, she spotted oceans of legs, hooves, feathers, and manes.
Then, the wave struck Rainbow Dash, and she curled up into a little ball, wincing. Her coat flickered in her peripheral, and she gasped, all the while flailing between the segmented skies. She looked down at her body. At one point, her skin was an ashen sheet of necrotic skin, covered in powdery snow. At another point, she saw that she was wearing the Loyalty pendant tightly around her neck. As soon as it all began, she was back to her normal self, and she hovered in mid-air, watching as the wave of distortion rolled off into the ether.
"What..." Rainbow gnashed her teeth. "...in the hay was that?"
In a flash of light, Epcot materialized back into the smiling, uniformed pony. "Starswirl's spell has been magnified by a race of alicorns for millennia!" She floated casually around Rainbow Dash. "That means tens of thousands of gods all magnifying the same schism in the dreamscape! Heehee! You can't do that much subconscious galloping without upsetting the neighbors!"
"The neighbors?" Rainbow Dash blinked.
Epcot grinned calmly. "Alternate dimensions! Parallel planes of existence!" She gestured while her mane glittered. "Think of them as... other Parks that you don't have a ticket to hop to."
"Is that really supposed to make me understand it better?"
Epcot blinked. "You mean it doesn't?"
Rainbow sighed, feeling around her neck for a weight that wasn't there. "So... what causes the wave?"
Epcot pouted. "I'm embarassed to answer."
"Try me."
"Neglect," the chaperone muttered. "I'm the only cast member that's been here after all."
"For real?" Rainbow squinted. "The alicorns only constructed one of you?"
"They only needed one." Epcot smiled faintly. "While they were still around, I was sufficient enough to help the dreamers around from Hub to Hub. But now... well..." She nevertheless sighed. "The dream became them." She pointed at another rippling wave of discordant atmospheres rolling their way. "And between the cracks, you—well—you see the other Parks. Heehee!"
Rainbow bore the brunt of another wave, shuddering. Through her left eye, she saw a bronze zeppelin gliding over a blighted landscape of snow and ash. Through her right eye, she spotted a crashed hunk of burning metal where a brown mare approached several dozen bipedal creatures.
"I think I much rather prefer the dream sims," Rainbow said.
"Really?" Epcot blinked, smiling. "I'm surprised!"
"Why's that?"
"Cuz, for a mortal, I smell the dust of broken dimensions on you! It almost makes me sneeze! Heehee!"
Rainbow simply stared at her. "You've been in here too long."
"I have?"
Rainbow sighed, diving down—or at least what she thought was down. "Let's just get away from these waves..."
Epcot morphed into a geodesic sphere—"YES"—and swiftly followed.