The Klingon battle cruiser commanded by Kang in 2268, crippled with the loss of most of its crew by an unseen entity and then destroyed by the Enterprise as a radiation hazard.
Kang's battle cruiser appears in the Original Series episode Day of the Dove. It arrives at Beta XII-A already badly damaged, and Kang tells Kirk that four hundred of his crew are dead in an attack he blames on the Enterprise, just as Kirk has been lured to the planet by a false distress call from a colony that never existed.
The survivors are beamed aboard the Enterprise as prisoners. Because the drifting cruiser is leaking dangerous radiation, Kirk orders it destroyed, which leaves both crews confined to one ship.
The alien entity responsible then keeps thirty-eight Klingons and thirty-eight Starfleet personnel fighting with swords so that it can feed on their hatred. Kang is seen in command of a different cruiser decades later, in the Voyager episode Flashback.