Swanhamr

A werewolf from the mythology of the following peoples:  Scandinavians, Irish, French, Germans, Czechs, Karelians, Estonians, Lithuanians, Latvians, Russians, Karelians, Kalmyks, Komi, Chuvash, Mari, Bashkirs, Kazakhs, Karakalpaks, yellow Uighurs, Buryats, Oirats, Khalkha Mongols, Chulym Tatars, Altai-Kizhi, Tuvinians, Mansi, Nenets, Evenks, Evens, Orochi, Yukaghirs, Chukchi, shatapatha-brahman.

This is a person (most often a woman) who can turn into a swan.