The sky cannon, a gigantic weapon, was built inside Mount Yeroc on Tahlboor by an old Tahlboorean society.
It drew energy from the planet's core and was moved around using numerous interconnected wheels.
The Tahlbooreans intended to reshape their planet and manipulate the tides by modifying the paths of their two moons. It annihilated one moon, seemingly leading to the collapse of their society.
Circa 5.5 BBY, Jake Harthan attempted to instigate a war of genocide between the Troobs and Hobors, to grant the Tion Hegemony access to the weapon.