[jonahbenton]

There are lots of good techniques here related to growth mindset and being ok being bad at something, etc. But I hear in this question something else- I hear an interactive, real time challenge, how to respond in real time to someone who gives you something scary.

That isn't a growth mindset problem, not really. It's a performance challenge. The domain that IMO has the best guidance is acting, specifically Improvisation- Improv for short.

There are many practices and techniques here for recognizing the fear and learning to ride it. "Yes, and" is one that was revelatory for me.

I highly recommend a book called Impro, by Keith Johnstone. And look for introductory Improv classes in your area (remote, of course). They are super fun, initially terrifying, but tremendously valuable. Should be a standard curricular class in all middle and high schools.

Cheers.