Tonton Streaming My Little Pony: Friendship Is Magic (2010) S1E6 - Boast Busters

A new unicorn called "The Great and Powerful" Trixie arrives in Ponyville, claiming to be the greatest magical pony in Equestria. Spike believes Twilight may be the one unicorn to put the arrogant braggart in her place, but she worries that she will lose the respect of her friends if she shows her true potential.