A Horn

A flash of scarlet light went to the back limbs and neck of a regal unicorn. A shriek arose from the gasping alicorn.
"Oh sister, if you won't let me have the sun, I'll kindly take it from you."
"Dash, I hope you know, before you kill me, no come here. I'll whisper it to you." Dash trot over to the sun goddess. "The secret is...." Dash was on the moon again.
"Goddess... the old hag's good. What hag? Why am I on the moon? Oh, Dash ha! Lemme tell you something. Rainbow's eyes went blank. You lost. The voice chided. Deep in her mind, Rainbow Dash saw herself prancing with glee. She looked closer. Flames. They consumed Canterlot. There was nothing left. "Listen bucko." Thought Dash, "I can control myself if I want to. I mean. I didn't kill anyone last cider season."
"Well, I am 20% more cunning than you."
"Hey! That's my catchphrase!"
"We'll you won't be alive for much longer, will you?"
"What the-"
"Never mind that. I'm hungry. Go eat for me!"
"No. Marshmallow, Cotton Candy and the Bacon Bros aren't here."
"We're going to Equestria."
"No wai-"
Poof.

"And that Luna is how-" Luna and Celestia saw a momentarily airborne wrestling match including a black alicorn and another of the species with a six color mane and cyan coat.

"Friggin-Dash are you-shut up!"

"Whoa!"

"Get out of this Luna!"

"Tia-"

"On it little sister" And the shadowy one was on the moon. Rainbow Dash looked at the princess with gratitude. Dash wondered what jealousy would do up there, but pushed away the thought of it. "Thanks biggest sister."

"Don't mention it." And that's what she said with a mischievous grin on her doll like face.