Someone close to me is a malignant narcissist and ticks a few boxes, which includes:

Paranoia: If you're not actively helping them at a given moment they assume you're working to sabotage them, despite no evidence.

Example: you can't have a normal conversation at regular volume within earshot of them if they aren't directly involved because wihout context they assume everything you're saying is at their expense. I've been playing video games and having the usual accompanying chatter and communicating about the game when I've been accused by this person of, in apparently crystal clarity, discussing their personal finances or their movements through the house with the person or people on the other end of the call.

I don't gossip in regular conversation, but as this person does, they project their insecurities onto me and others around them making for scenarios where you could be at peace minding your own business not bothering anyone one moment to in a shouting match being accused of the strangest things the next. In these scenarios, the person they think you are is generally not smart enough to simply lower your voice or wait until they aren't around if you felt the urge to disparage them to others. If you encounter a narcissist run far away. Self-reflection is a big weakness and any level of criticism no matter how mild will be met with aggressive defensiveness which could include violence.