My Little Pony: Friendship Is Magic S00 E42 Ail-icorn

Twilight Sparkle's spring allergy manifests as a cold in her horn - every time she sneezes, something magical (and odd!) happens. After her uncontrollable horn-spray causes Rainbow Dash to speak in sound effects and nearly freezes Fluttershy, Pinkie arrives with a cure from Zecora - with a tiiiiny side effect