Chulak's planet killer

The planet killer was an automated starship, a doomsday machine in Romulan Star Empire service in the 2260s decade. The vessel was delivered by Specialist Krog of the Na'kuhl to Commander of the Romulan Imperial Star Navy at Galorndon Core. 

Service history and disposition
Circa 2267, the Envoy of the Temporal Liberation Front sent Specialist Krog of the Na'kuhl to Commander Chulak in a bid to ally against the Federation. Krog delivered the planet killer and a control unit to Galorndon Core. The Romulans were skeptical of the Na'kuhl's promised superweapon. In response, the Federation Temporal Agency tasked their operative Timot Danlen with protecting the timeline. Danlen, known as Daniels, recruited an Alpha Quadrant Alliance starship from the 25th century to investigate alteration. Holographically disguised as the bird of prey, the Allies scanned Chulak's planet killer in Galorndon Core's orbit before infiltrating Chulak's base on the surface. During a conference between the Romulans and Na'kuhl, the Envoy appeared and pointed the interlopers out. Following a firefight, the Allies destroyed the Na'kuhl control unit and returned to their ship. Daniels was working on fashioning a control unit. When triggered, the planet killer went rogue and destroyed a squadron of Vas Hatham birds of prey. Chulak ordered the remaining Romulan vessels to fire at the Na'kuhl and their superweapon, to prevent the doomsday machine from destroying the planet.

The planet killer was disabled when the damaged Na'kuhl destroyer NV fell into its maw. Briefly thought by the Romulans and Allies to be rendered inert, the planet killer instead tumbled towards Galorndon Core, descended through its atmosphere and crashed into the surface. The resulting cascade rendered the planet permanently uninhabitable. Chulak thanked the Allies for helping the Romulans fight the machine and ordered them to leave.