15 years ago I had a horrific experience as a speaker at an international conference.
In the middle of my presentation, I heard a whisper - not so loud to be considered a rude interruption but loud enough so everyone can hear.
"Ah, go make me a sandwich or something."
For a moment my mind went completely blank.
I finished my presentation only to find my audience at their feet, applauding.
It turned out (yes, I didn't remember anything past that sinister whisper) that I replied with:
"Hmm... I was pretty sure this conference wasn't for kids. I'm busy right now sweetie, go ask your mom!" and then I continued talking.
You see, I was new to this world of suits, high-heels, and power games.
However, I played video games long enough to know how to deal with a 12-year-old who compensates for their lack of skill with toxicity.
Whenever someone tries to intimidate you using status or power imagine how ridiculous they would look in a situation you feel quite comfortable with.
Basically - treat them like boggarts!