The Oompa-Loompas are fictional characters from Roald Dahl's children's book, "Charlie and the Chocolate Factory." They are small, orange-skinned beings known for their distinctive green hair and cheerful demeanor. In the story, they work in Willy Wonka's chocolate factory, where they help create various candies and treats. Oompa-Loompas are also famous for their catchy songs, which they sing to convey moral lessons about the children who visit the factory. Their playful nature and unique appearance have made them iconic figures in popular culture, often associated with themes of fun and responsibility.