Silence is incredibly effective. A pithy response I like a slow and considered Fuck Off personally can get you into trouble or cause things to degenerate into a slanging match where you come out of it looking as bad as they do.
Nature abhors a vacuum - and so do some people who enjoy intimidating others or having power through barking at them like dogs. Silence isn't the expected reaction, it's tears or barking back.
[tirade of nonsense]
Silence,
Silence. Just looking at them.
[tirade peters out]
Silence. Just looking at them.
or
[Tone is being to feel a little charged]
Immediately becoming absolutely still and looking at them.
[Tone changes pretty sharpish because they've understood the body language of the 'what the fuck did you just say to me?' and you're clearly not just in control as you're calm and collected, you have silently told them that there is a totally unpredictable yet totally within your control response coming their way - all well and good]
[Tone continues in the same way]
Wait. No answer. No excuses, apologies, tears or shouting/being rude back.
Wait.
Wait.
They run out of filler to add to their noise.
'Okay'.
In my experience, the people who do that sort of thing often double down over email, at which point there's something to forward to HR whilst you remain completely immune to criticism as you haven't joined in with a slanging match or verbal punch up. And other people notice. They shout or are otherwise rude, you're the one who doesn't appear to react but remains in control.
It's not The Silent Treatment. There just isn't anything to be said that could improve the conversation rather than add fuel to the fire - and when somebody is confrontational/belligerent, they want more fuel because that's why they're doing it in the first place. I've dealt with bigger, scarier and ruder people than them and, frankly, as I'm not likely to be dangling two foot off the ground with somebody's hand around my throat anymore, they really aren't that significant in the great scheme of things.
I've experienced a few places where somebody initially mistook quiet for weakness. They've all learned not to do it again, whether it's been through a polite email to their line manager with accompanying email trail and a brief explanation that this followed a conversation in which they shouted/informed me that I was a xxxxx, somebody else reporting it or filing a formal grievance where they had to give me a public apology for their totally unacceptable behaviour. Which definitely hurt them far more than what they had said ever hurt me.