imaginary purple key

The imaginary purple key is where in either Guitar Hero or Rock Band where the player has to shift his hand to hit the orange note and over shifts to where the player's pinky is on the fretboard and their ring finger is on the orange key.

Jeff: "Having played several green notes in succession, saw that he had to shift down to hit the next note, which was an orange key. Quickly, he moves his left hand down to the right and squeezes his pinky down on the neck of the guitar controller and strums up. Staring blankly at the screen he sees that he missed the note. Swiftly glancing down Jeff is dumbfounded. Discovering that his pinky was on the imaginary purple key."

John: Saw that. You're a dumbass.