D.M.
Luckily, there don't seem to be many kids that bully, at least to my kids, but if you come across another one, tell the child to be nice to your child, then if he still bullys and hurts your child, find the mom and tell her, but don't yell at her, be nice about it and hopefully she won't get all defensive and mad back at you, which she has no right to do - it would be very rude of her if she did that. Then just stay close to your child to make sure the bully doesn't do it again.