The Corbomite Maneuver

The Enterprise find an odd, glowing cube floating in interstellar space, which must be destroyed after it begins to emit dangerous radiation. Following the cube's destruction, an immense, glowing sphere called Fesarius races to the Enterprise's location, controlled by Balok, an alien who announces that he will destroy the Enterprise in retribution. Captain Kirk manages to bluff Balok into believing the Enterprise contains a deadly substance called Corbomite, which would severely damage any attacking ship. After managing to escape the Fesarius's tractor beam, disabling the alien ship, Kirk and a landing party board the sphere, discovering the true identity of the vessel's controller.[37]