I have a 3 year old black lab mix and earlier today, he bit an 8 yr old child that came over to play with my children. The child happened to be chasing my two daughters, in a playful manner, around the house with a plastic baseball bat pretending he was a super-hero. I didn't pay much attention to it at the time because my dog hasn't really been aggressive in the past, but in hindsight, I should have not allowed the child to run around the house with a Wiffle Ball bat. I witnessed the entire thing: as the child ran by my black lab with the wiffle ball bat raised in the air, chasing my 6 and 8 year old daughters, my dog suddenly snapped and caught the child in the upper arm (in the tricept area). The child fell to the ground screaming and wasn't bleeding but had visible bite marks where my dog had snapped at him. To make matters worse, his parent witnessed it too and I was struggling on how to handle the situation. On one hand, I was upset with my dog because I've never seen this happen before. On the other hand, I sort-of understand why he did it: he saw someone chasing his family members around the house with a bat. I apologized to the childs mother a few times and made sure the child was OK as he is a very nice kid that we have over frequently. But I'm struggling with what his parents think. He comes over to play often and I'm worried that his parents won't trust their kids around our dog. So I'm wondering if I should put my dog through training or what I should do. He's a pretty good dog most of the time, however, we do have issues with him jumping up on people when we have guests over, not coming when hes called, and other minor issues but now I'm nervous about him snapping around the neighborhood kids. Does anyone Have any ideas or feedback?