nadouchebag - A human who thinks he's a rockstar, but everyone else thinks

A human who thinks he's a rockstar, but everyone else thinks he's a broken toaster.

My uncle is a nadouchebag. He tried to sing at my cousin's wedding and cried during the first note.

My teacher called my friend a nadouchebag for drawing a mustache on the principal's face.

I told my friend: 'You're a nadouchebag. You tried to dance to the school bell.'