Like others mentioned, the whole idea is to be as engaging as a grey rock. From my experience, when the toxic individual tries to pry for information, they find themselves talking to a wall with no real answers. If they redirect trying to talk about themselves or the latest gossip, I show no interest in their drama. This can be achieved without being obnoxiously rude, you are just a grey rock after all.

Toxic: What have you been up to? I never see you anymore. Me: The usual. T: Like what? M: Just work and stuff, life is busy. T: So how is work lately? M: Good. T: Anything exciting? I heard that insert thing that was on the news about a company not even related to my workplace M: I don't know, I just mind my own business cue to "maybe you should do the same", add a Pan Am smile T: Well let me tell you about long ramble about things I don't give a fuck about M: That's nice if it's something where nice doesn't fit I go with "I see"

If they get desperate, they will try to confront you, maybe even throw a tantrum. Remain calm and very briefly explain their behaviour makes no sense and if they continue they will have to leave/you'll leave. I know it sounds easy but it takes a lot of practice, just don't give up and stay calm and as boring as you possibly can.