Tonton Streaming Voltron: Defender of the Universe (1984) S1E50 - Zarkon Becomes a Robeast

Lotor fails to capture Planet Arus and allows the Voltron Force to capture the Pulsar Cannon. For his incompetence, King Zarkon has his son imprisoned! Princess Allura and her alliance of local planets see their chance to launch a counterattack on Planet Doom itself.