Maddy Bites Mylee

Last night was the first time since Mylee has been born where Maddy intentionally hurt her sister. While I was holding Mylee facing out, Maddy was playing with her feet. The next thing I knew Mylee was screeching. I looked down to find Maddy biting Mylee's toes. Thank goodness Mylee had socks on otherwise I think she would have broke her skin. There were some good teeth marks across the base of her toes though. Poor Mylee! I wasn't sure how to handle this one as I was ready to beat Maddy or bite her back...I told her next time I will. So within the last week Maddy has tested me twice...last week it was a slap across my face in the grocery store. I sure will take the "terrible two's" over the "trying three's". Maddy actually was a "terrific two" if you ask me but something has drastically changed the last few months. HELP!