My Little Pony friendship is magic season 2 episode 6

When visiting Zecora's hut to receive medicine for her chipped tooth, Apple Bloom finds a "Heart's Desire" flower which can make "talent come into view." When Apple Bloom believes it could help her finally discover her special talent, she instead becomes afflicted with the "Cutie Pox", which causes various Cutie Marks to appear on her body, and forcing her to continually perform the talents they represent.