Ep 50. Zarkon Becomes a Robeast

Lotor fails to capture Planet Arus and allows the Voltron Force to capture the Pulsar Cannon. For his gross incompetence, King Zarkon has his son thrown in the dungeons! Princess Allura and her alliance of local planets decide that now is their one chance to launch a counterattack on Planet Doom itself. They disable Planet Doom's shield with a shot from the Pulsar Cannon and charge in, only to be faced with the ultimate Robeast: King Zarkon himself!