Princess and the Frog

Origin
In the tale, a spoiled princess reluctantly befriends a frog (possibly meeting him after dropping a gold ball into his pond), who magically transforms into a handsome prince. Although in modern versions the transformation is invariably triggered by the princess kissing the frog, in the Brothers Grimm version of the story, the frog's spell was broken when the princess threw it against a wall in disgust. In other early versions, it was sufficient for the frog to spend the night on the princess's pillow.