Царевна-лягушка
A similar tale type is ATU 402, "The Animal Bride". In these tales, a female animal (mouse, cat or frog) helps a prince with three tasks and after marrying him, gain assumes human form. In "Puddocky" (old word for toad), another German folk tale, and likewise "Tsarevna Lyagushka" ("The Frog Princess"), a Russian folk tale, the male and female roles of the frog prince are reversed. Prince Ivan Tsarevitch discovers the enchanted female frog, who becomes Vasilisa the Wise, a sorceress.