The Klingons used a terrifying weapon during their first appearance on Star Trek: The Original Seriesthat has never been shown on screen. Since their debut in TOS season 1, episode 26, "Errand of ...

Before long, the Klingon Commander Kor (John Colicos) arrives and declares himself military governor, while his crew of Klingons seize the planet. Although Kirk poses as a local, Kor can see that ...