@sakura656 I'd be like "And my fat ass is about to knock you down, bitch, do you really want to tango with someone twice your size? Cuz I'll sit on you till you cry. Let's go!"
I'm the type that takes comfort in humor, particularly humor directed at myself, and I get... aggressive XD
As for what SHOULD be done, hard to say. Getting aggressive usually doesn't fix anything, and parenting is hard- I am actually terrified of the day that my son accidentally does something to another kid, because I am afraid that if a parent aggressively approaches me- even though I'd NEVER stand for him being a bully or doing something mean- I'd 100% get down to fight with a parent being aggressive. I get they're defending their child, but I want to defend mine, too- that's my baby.
Only thing I can think of is going to security or something like that and saying she's harassing you and verbally attacking you. I don't know that I'd be able to be the bigger person enough to do this, because I'm aggressive and defensive and I'd immediately be down to tango (verbally- I'm too clumsy to be able to win an actual fight), but that's not exactly the RIGHT thing to do, just the reactionary thing to do, lol.
I am sorry this happened... What a terrible person. She'll spend the rest of the day villifying you to make it seem like she's the hero, and editing the story so that her child just "lightly tapped" your child and "took the carrot when she dropped it", which is obviously not what happened.