You've probably heard a certain phenomenon so much that you stopped noticing it. But Patrick Metzger, writing for The Patterning , called out the weird commonality perfectly: the Millennial Whoop.So what is this phenomenon, which you will now never be able to unhear?Metzger writes: "I like to call this melodic snippet the 'Millennial Whoop.' It’s a sequence of notes that alternates between the fifth and third notes of a major scale, typically starting on the fifth. The rhythm is usually straight 8th-notes, but it may start on the downbeat or on the upbeat in different songs. A singer usually belts these notes with an 'Oh' phoneme, often in a 'Wa-oh-wa-oh' pattern. And it is in so many pop songs it’s criminal."Confused? Don't be. It's all over this Katy Perry song, starting at 0:51, then at 1:05 and multiple times throughout the chorus.