SEASON TWO SPOILERS PRESENT
Magical vanishing cutie mark! without the use of horn!
spotted by stuff456789

checked the iTunes copy, error persists :(

from My Little Pony: Friendship is Magic S02E01 "The Return of Harmony Part 1"

My Little Pony owned by Hasbro, MLP: Friendship is Magic created by Lauren Faust.
Encoded at highest image and sound quality possible for .f4v
...for a 480p DVR-rip :|