The Sea-Hare facts for kids
It is Aarne-Thompson type 554, The Grateful Animals, and similar to 851, Winning the Princess with a Riddle.
Stith Thompson classified the tale as AT 329, "Hiding from the Devil (Princess)", tales where the hero must hide from the princess's mirror or windows that can peer into the whole world.
A princess had a magical tower with twelve windows, and whenever she looked from a window, she saw more clearly from it than the one before. Being haughty, she had no wish to marry, and decreed that any suitor must hide from her to win her, but if she found him, he was to lose his head. After ninety-seven lost their lives, three brothers presented themselves, and the first two lost. The youngest son asked for three tries. He went hunting and spared a raven, a fish, and a fox. The raven tried to hide him in an egg, where he could be seen only from the eleventh window. The fish swallowed him, where he could be seen only from the twelfth. The fox turned him into a pretty sea-hare and sold him, to the princess. When she went to the windows, he hid in her hair. She could not see him and angrily threw the sea-hare out of her hair. He sneaked off, the fox restored him, and he went to claim her, and they married.
Two Hungarian variants of the tale were adapted into episodes of the Hungarian television series Magyar népmesék ("Hungarian Folk Tales") (hu), with the titles Zöld Péter ("Green Peter") and Kiskondás ("The Little Swineherd").
The Sea-Hare Facts for Kids. Kiddle Encyclopedia.