The solid rock was carved into a likeness of a Kinitawowi skull. It served as a warning beacon to any spacecraft entering GELF territory, and replayed a prerecorded message proclaiming "death to the stranger" in Kinitawowi speech (as Kryten replayed through the Universal Translator). It unclear whether this was a warning to humans, Felis sapiens, mechanoids or simulants.
A Space Corps Enforcement Orb once almost destroyed Starbug, carrying out a death sentence since it had found them guilty of looting derelict Space Corps spacecraft, the Deep Space equivalent of horse rustlers in the Old West. The pulse missiles caused hull damage to the 'bug, destroying the Oxy-Generation Unit, fuel leakage, and set the 'bug ablaze. Numerous flares and decoys were launched to throw off the missiles, but the Enforcement Orb kept coming.
Starbug was saved when it flew into the eye-socket of the skull-like GELF icon carved into a moon. The icon was destroyed in the last blast, but the 'bug was saved - barely. As the 'bug fled into the GELF Zone, not even the Enforcement Orb would dare follow, and it gave up the chase.
The boys from the Dwarf were then able to crash land on a nearby Kinitawowi moon with an ocean, putting the flames out. With auto-repair able to take care of everything else, the crew then had to go out and trade with the locals for a new Oxy-Generation Unit. ("Emohawk", Series VI)