"Rainbow Factory" is a fan-made story set in the universe of the animated series My Little Pony: Friendship is Magic. It explores a dark and twisted version of the colorful world, focusing on the production of rainbows. The narrative reveals that rainbows are created through a sinister process involving the exploitation of Pegasi, who are captured and used to generate the vibrant colors. The story is known for its unsettling themes and contrasts sharply with the original show's lighthearted tone. It has gained popularity within the Brony community, leading to various adaptations, fan art, and discussions about its deeper meanings and implications.