The fighting on Immalia referred to a Galactic Civil War engagement between the Galactic Empire and the Rebel Alliance on the planet Immalia prior to the Battle of Yavin. Rebel forces retreated upon sighting approaching Imperial radiation zone assault troopers, believing they were fighting in an area exposed to radiation. Only later did the Rebels learn that the Imperials merely had access to radtrooper armor that day and that they retreated for nothing.