In the 2260s, a secret Klingon military research outpost was established on Seggor, hidden underground. The base had a retractable landing pad for spacecraft as well as a few small, hidden turbolifts to the surface. The facility included a control room and a large laboratory containing an experimental granulator, an energy weapon of mass destruction which could be used at close range on a table or fired at long range through a cannon.
In 2266, a Klingon strike raider lured the Federation starship USS Enterprise to Seggor, then seemed to disappear from sensors. A class F shuttlecraft led by James T. Kirk, Hoskins, and Hikaru Sulu searched for the raider. Hoskins and the shuttle were subjected to the granulator as a demonstration of its power. Kirk was told to relay an ultimatum for Earth to surrender or be disintegrated. As Kirk retreated, Montgomery Scott sneaked into the base and sabotaged the exit hatch for the cannon. When the strike raider's commander ordered the cannon to fire at the Enterprise, it overloaded and destroyed a dozen square miles of the planet's surface, eliminating the weapon, the base, and the strike raider. (TOS comic: "The Klingon Ultimatum")