This list of mythical creatures that begin with this letter and I am constantly gathering information from each continent, and is continually being updated.
Werehyena (Africa)
Werehyena in the folklore of the Arabian Peninsula, the Levant, North Africa, the Horn of Africa, and the Near East as well as some adjacent territories. Unlike werewolves and other therianthropes, which are usually portrayed as being originally human, some werehyena lore tells of how they can also be hyenas disguised as humans.
In Somalia, it is traditionally believed that Qori Ismaris ("One who rubs himself with a stick") was a man who could transform himself into a "hyena-man" by rubbing himself with a magic stick at nightfall and by repeating this process could return to his human state before dawn.