Years ago, the Voltron Force ultimately defeated Prince Lotor, resulting in h...
Voltron: The Third Dimension
Season 1 Episode 6: Shades of Gray
Haggar casts a spell on Hunk, turning him against the rest of the Voltron Force. The spell also turns Yellow Lion into a destructive Gray Lion. The rest of the team have to find a way to save Hunk and rescue Amalgamus from Lotor.