Alicorn Pinkie shrugged, lighting her horn.
"NO!" not-Alicorn Pinkie yelled, diving out of a portal and tackling her ascended counterpart. "Don't do that! You'll break reality!"
"Whuh--" Alicorn Pinkie blinked. The wings and horn on her began to fade away. "Oh, hi, me! Wazzup?"
And so the universe was saved(?) from a never-ending time loop of Pinkie ascending infinitely many times.