|“||Stop! Why do you have to ruin everything!?||„|
|~ Sweetie Belle to the Rarity Cloud.|
The Rarity Cloud was the figment of Sweetie Belle's nightmare and the main antagonist of the season 4 Episode 19 "For Whom the Sweetie Belle Toils" of My Little Pony: Friendship is Magic.
In the episode, Sweetie Belle helps Rarity create a headdress for Sapphire Shores, the Pony of Pop. In return, Rarity creates outfits for a play that Sweetie Belle wrote, directed, and is starring herself. However, after the play, none of the ponies seemed to have paid any attention to the play other than the dresses, making Sweetie Belle very cross with her older sister (though Rarity only did what she was asked to do).
In an effort for bitter payback, Sweetie Belle purposely sabotages Rarity's headdress while she slept. Feeling satisfied, Sweetie Belle fell to sleep. While asleep, she has a dream where she is the winner of the "Best Writer/Director/Actor-in-an-awesome-play-put-on-by-a-pony-and-her-awesome-best-friends" award. But during the ceremony, a thunderstorm breaks out, and everypony runs away, despite Sweetie's pleas not to. Her trophy begins to melt, and she hears a maniacal laugh. She looks up, and sees a storm cloud in the shape of Rarity's face. Sweetie Belle demands that she'd desist, but the Rarity Cloud attempts to strike Sweetie with a thunderbolt, but Princess Luna intervenes, shielding Sweetie Belle, and dispersing the Rarity Cloud into nothing.
After the event, Luna consoles with Sweetie Belle, knowing what it feels like to be overshadowed by an older sister. Luna then shows Sweetie visions of her past, present, and future to help her realize that her jealousy will only cause misery, just as Luna's once did. She then helps Sweetie fix the headdress, and adding a little dolphin in the center, which are Sapphire's favorite animal. After which, Sweetie Belle apologizes to Rarity for her jealousy, which she accepts.
- The Rarity Cloud seems to symbolize Sweetie Belle's jealousy of Rarity, just as Nightmare Moon symbolized Luna's jealousy for Celestia.