The "Frog Prince" is a classic fairy tale about a princess who encounters a frog that claims to be a prince under a spell. The frog asks her to fulfill a promise, which involves her allowing him to stay with her. Initially reluctant, the princess eventually agrees, leading to a surprising transformation. When the princess kisses the frog, he turns back into a handsome prince. The story highlights themes of promise, transformation, and the importance of looking beyond appearances. It is often associated with the Brothers Grimm, who popularized the tale in their collection of fairy tales.