A song written by The Ramones (specifically by Dee Dee Ramone) in 1977 on their "Leave Home" album. The lyric goes: "I don't wanna be a pinhead no more. I just met a nurse that I could go for...D-U-M-B Everyone's accusing me!" The song was inspired by the movie "Freaks" and the comic "Zippy the Pinhead." The word "pinhead," in this context, refers to an outcast/freak/childish character with a cone-shaped head.
"Jo is wearing an outfit that looks different from what everyone else in the school is wearing. What a pinhead."
"Jo's head is pretty pointy at the top. I wonder what it must be like to be a pinhead."
"Gabba Gabba Hey!" - The Ramones