Dorg and the Pony Prance - S1.E17

Dorg wishes to win a trophy since Voulez has won many and he hasn't won any, so he enters a horse-racing competition at the mall with Jet posing as his horse. However, in order for Jet to compete, Patronella uses a magic spell to conceal his horn - and without his unicorn horn, Jet loses his confidence and has magical indigestion that causes unexpected negative consequences during the race.