G.U.N. - Guardian Units of the Nation.
Maniacal military organistion, which appears in Sonic Adventure 2.
Military forces include: Helicopters similar in appearance to Russian Hinds, Mechs armed with machine guns, rockets, and laser cannons, Hundreds of robot drones called Hunters, who all seem to have very small feet, and thousands of soldiers, agents, commanders, thieves, news reporters, door-to-door salesmen, etc.
G.U.N. are responsible for the deaths of the research scientists aboard the Space Colony ARK.
Because of this, they will pay.