“Um … not complaining or anythang but how do ya expect us ta prank Dash when 4 out of 6 of us can’t fly or aren’t pegasi?” Apple Bloom asked.
“I can fix that Apple Bloom,” Discord said with a snap of his fingers. After a bright flash of light there were two pegasi, and one horned pegasi.
Scootaloo pointed at her friend and said, “Sweets! You’re an Alicorn! Discord, why can’t you make the rest of us Alicorns?!”
Sweetie Belle hearing that she was an Alicorn, and to her mind a Princess pranced in place and squealed so hard that it came out as an excited, loud whisper, “I’m a Princess! I’m a Princess! *Squee*!”
Discord was about to say that it wouldn’t be a good idea when a good idea struck him, If I make them all horned pegasi, not true alicorns than it would still stir enough chaos to be fun. And I’d be helping my friends. Oh! I love working with loopholes!
With another flick of his fingers each of the others sprouted horns from their heads. With a squeal of joy they shouted in unison, “Cutie Mark Crusader Princesses! Yay!” Just as their hoofs touched one anothers an explosion of rainbows and smoke shot from them and when the light died down, and smoke cleared stood a speechless Pinkie Pie.
“Well … that wasn’t expected.” Discord whispered.
“What wasn’t expected,” Pinkie asked.
“Well I didn’t factor the power of friendship mixing with the powers of chaos like they did. I simply gave them wings and a horn without the full magic of the other races, they were simply winged pegasi. But now they actually are Alicorns, and …,” Snapping his fingers repeatedly, nothing happened, “I can’t undo it. Oh! This is amazing! Nopony told me Hearth’s Warming Eve was coming early! Quick Pinkie where is Santa Hooves and his army of little mules?”
http://www.fimfiction.net/story/149274/2/foalsitters-of-chaos/the-foalsitters-of-chaos