The Mimic

I have a kid in one of my junior classes that mimes and mimics everything I say or do.  He is a nice kid and always smiles but his behavior is disturbing.  He often mimics not only actions but words, instructions, mannerisms, coughs and any other thing he can.  I have told him to stop and often the homeroom teachers do too but I have come to the conclusion he has a mental issue.  He often mimics his classmates too and he has ostracized himself and built a wall between he and his classmates due in large part to this weird mimic issue he has.

It's like he's trying out for a Hollywood role or something like that.  I don't know how to stop him so I have resigned to ignoring it and trying to flow along with the lesson as best I can.  He knows he is disturbing everyone but it's an obsessive behavior that he can't control even after being lectured, scolded or punished.  The other teachers just tell me to pretend not to notice because that's the only thing that seems to work.  But it sure does make for an odd lesson.