My Little Pony: Friendship Is Magic (2010)

S2E8 The Mysterious Mare Do Well

A mysterious masked hero is overshadowing Rainbow Dash, claiming the title of Ponyville’s top defender. As this unknown figure begins to gain fame, Rainbow becomes determined to reclaim her status and prove that she’s still the best when it comes to heroics. With her signature determination, she sets out to uncover the identity of this new challenger and show that she can’t be easily replaced in the hearts of her fellow ponies.