This list of mythical creatures that begin with this letter and I am constantly gathering information from each continent, and is continually being updated.
Kupua (Hawaiian)
Hawaiian myths and legends abound with such characters. They are traditionally described as monsters having the power of appearing in different kinds of bodies. They usually have cruel and vindictive characters and are ready to destroy and devour any persons they can catch. There are, however, many kupuas of kindly spirit who give watchful care to the members of their own families.
Mamala the surf-rider was a chieftess of kupua character. She might appear as a shark, a lizard, or a woman. Her surfing skills were so impressive that people would gather on the beach to applaud her performance. She was married to the shark-man Ouha, but later left him for a chief named Hono-kau-pu.