To be succinct and private.. My incubator worked me for weeks to build rapport and trust with me in my younger days, to get me to tell her a something that she would ultimately, and immediately use and weaponize against me and others.
This wasnt the first time I tried to have a relationship with her, but it did finally open my eyes and become the last. In the many many decades since, I've not so much as acknowledge her existence when crossing paths.
It wasn't just one big thing (although there were plenty of those), it was death by 1000 cuts. In the end it was something relatively small. I asked her to remove me from her regular right-wing email blasts and she refused to do so. What kind of asshole refuses to do something so small for a complete stranger, much less a family member? A malignant narcissist asshole.
If you haven't read up on narcissistic family systems there's a lot of good content out there. Here's a short article.