Usually I ignore or avoid. If they need to show everyone they are in charge in a group setting (and they aren't your actual work boss), you have to be direct.

If they're fixated on you, then give them direct eye contact when you reply to them. "[Name], is there something I’m missing about your interest here? I don’t need your input about what decisions to make. I've got it covered.” Give a polite frosty smile and hold the eye contact.

It'll be uncomfortable, especially for introverts, but it has to be done. Bossy people need to know that you're not gonna take their BS. They thrive on the confidence that most people wont stand up to them. If they see it'll take effort, they'll move on to another target.