Xena: Warrior Princess (1995)

Season 6: Episode 8

Gabrielle, Brunnhilda and Beowulf find Xena alive after the Grindl's attack. When they arrive to the mine where the Grindl is hidden, Xena reveals the monster was once the valkyrie Grinhilda, who put the Rheingold Ring on her finger as a desperate attempt to stop Xena's reign of terror.