Shoot the Core! is an infamous phrase that was first uttered in Gradius II and has continued to be used in various games throughout the series. The phrase is usually said at a boss which has a Core (eg. Big Core MK I) or a blue sphere that was the heart of a mechanical boss. The voice would shout "Shoot The Core!" letting the player know what to target in order to destroy the boss. There are other phrases connected to weak points of the boss (eg. "Shoot the eye!" "Shoot the head!")