Supergirl (1984) on Netflix

Introducing a brand new superhero--the beautiful and mighty Girl of Steel in her very first adventure. Her name is Kara, and she's Superman's cousin from Krypton. Coming to Earth on a mission to save her dying city, Supergirl has to find and recover the Omegahedron, a source of almost unlimited power. But it's fallen into the hands of an amateur witch named Selena--who intends to use it to rule the world! To get it back, Supergirl has to fight not only evil humans, but the unimaginable forces of Black Magic (including a hundred-foot monster made of pure energy), and make a perilous journey into the forbidden depths of the Phantom Zone.