S01E45: Eye of the Beholder

A severe drought has suddenly consumed Planet Eternia, causing plants to die and machines to malfunction- even He-Man himself is weakening. As the oxygen in the air becomes less and less, He-Man sets out to find the cause of the problem. His investigations lead him to the Sea of Eternity, where he teams up with an insect man called Garth to solve the problem- which is being caused by none other than Skeletor, who is using a pumping machine to drain the sea.