Proteus

n.
  1. (Class. Myth.) A sea god in the service of Neptune who assumed different shapes at will. Hence, one who easily changes his appearance or principles.
    1. A genus of aquatic eel-shaped amphibians found in caves in Austria. They have permanent external gills as well as lungs. The eyes are small and the legs are weak.
    2. A changeable protozoan; an amœba.