Here's a quick lesson for ya: Don't mess with Solange Knowles… or any mother for that matter!

The 29-year-old, who posted a picture of her 11-year-old son, Daniel Julez J. Smith, Jr., in an LL Cool J costume this weekend, was appalled when a fan wrote next to the image, "So cute but at the same time he ugly."

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Like any protective mother would, Solange replied to the hater, but managed to keep a relatively cool head, writing, "Jussst as I thought it was safe to share pictures again, a young'n like you decides to use her time to spread ugliness."

She continued, "I don't fault you, I can only imagine why you would feel the need to say such things, but thanks again for being a reminder…that when I open up a space for an innocent beautiful being like my boy to be criticized and judged, I WILL most likely respond."

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The "Losing You" singer added, "I hope that this really resonates with you and you make better decisions in the future towards how you use your words towards innocent children."

#PREACH. Needless to say, the troll's account has magically disappeared since being called out on Instagram. Funny how that always happens…