YOU'RE A POOPY HEAD comes from a youtuber called "angry video game nerd" with the words "YOU'RE A POOPY HEAD! DO WE NEED TO SPELL IT OUT?! YOUR A POOPY HEAD!" and thus creating an internet legend
you know the "YOU'RE A POOPY HEAD!" meme right?
An insult used by people under the age of 8. It is used when a child calls someone a "Poopy Head" It is also used in a joking manner by people over the age of 8. The word "Poopy Head" is basically "Sh*t Head" but for toddlers.
Child 1:" WHY DID YOU BROKE MY LEGOS?!"
Child 2: "Because "You're a poopy head!"