When a person acts abnormally, it means he should be treated in a different way (psychologically). Don't ever label anyone 'bad' or 'idiot'. Try to solve the problem without showing any reaction. It is really very difficult but tries to make him your friend or at least a person who has good term with you. Don't afraid of him. Get closer to him, say compliments (salam), smile and shake hand. Initially he would show a rude behaviour with you but after some time you will see he is going to accept you and he will like to play with you. You can help him in his studies so he would be grateful to you and will never tease you Insha Allah.