I second what Cat says, and would like to add, that this sort of behavior seems to be "catching".
Honestly, since I termed my fearsome foursome, and enrolled new kids, everyone here is doing fantastic, EXCEPT the one kid left from the old group!
He used to be a dream, but after a year of being with the fab four, he has a lot to unlearn! He is 2, so that doesn't help, but we have some work cut out for us...sigh...
I see the new kids comming here already are shunning him a bit because THEY don't like his behavior. I have talked to them about how the kids that used to come here were mean to him, and now we all have to be good friends and help him learn to be kind. I hope it works, because I love this little man and I love his family!