Conquering planets.

[Randallw]

A plot device in the Thrawn Trilogy was that they sneaked a cloaked ship into low orbit of a planet (Cloaking being unique, they only had one ship). A whole fleet arrives so the defenders activate their invulnerable shield, which extends to high orbit. The fleet fires and as its fire hits the shield the cloaked vessel (still cloaked) fires. The defenders seeing that the empire has a new weapon capable of defeating shields surrenders.