The Golden Crab

 
The Golden Crab, or 'Kaa Dhahabu' in Swahili.
 
"The crab sent the fisherman to fetch rich garments for himself and his bride, and had himself carried to the castle on a golden cushion. After the wedding, he told his bride that he was an enchanted prince, a crab by day and a man by night, though he could change himself into an eagle whenever he liked." — Bernhard Schmidt