He-Man and the Masters of the Universe (1983)

S2E15 The Arena

Man-At-Arms successfully establishes communication with a benevolent alien known as Om, who is floating above Eternia. As the citizens of Eternos greet Om warmly, Skeletor, alongside General Tataran and the Goblin Army, launches an attack on the city. A brutal clash ensues, leaving Om bewildered by the violence, as his kind is unfamiliar with conflict. To determine which side possesses greater wisdom and strength, Om chooses He-Man to represent the forces of good and Skeletor for evil, forcing them into a decisive showdown.