Tragically, there are some very young candidates for this title:
The third grader who, when asked to complete a worksheet, states, “I’m not doing this. I need to save my brain for video games.”
The child who runs the halls, terrorizing anyone younger or with a limited understanding of English. He goes all stealth, squishing himself into a corner of the hallway that, while obscuring him from one side of the hall, is in full view of my classroom door. “You do know that you are not invisible, right?” I ask. He says nothing.