I know this sucks, it’s not fair, and in a perfect world this would absolutely be something people like us would never have to deal with. When I was younger, situations like this would make me feel so helpless and angry. You really feel like a prisoner in your own head. Unfortunately, you could go to HR, but depending on the company you work for, this might be wasted energy. The most that might happen is he gets talked to and he stops for a little while. People who do what your boss did don’t respect rules about teasing people and he’ll probably just figure out new ways to antagonize you. There’s a million ways to tease without really teasing. Or you have a great HR and it’s handled Perfectly in your favor, but I’ve never seen that happen in my career as someone who stutters. The one sure thing I’ve found to work with making people think twice about doing this to me is just getting good at giving shit back. It’s pretty easy when you think about it, stuttering is something you can’t control, it’s not your fault that you do this, so anything that falls in that category is on the table. Is he fat, bald, ugly, smells weird, not great with women? You can use any of this, make it vaguely clever or funny, and if he cries about it, point out how lame it is that he wants to roast people but acts like a baby when it’s thrown ack to him. Don’t get too wild and scream “your dad is dead!!” coz you’ll look like a psycho, but you get the idea. Make sure you do it in a fun, light demeanor. You’ll gain his respect, make him look like an asshole and make him second guess doing this again. A lot of people who tease stutterers don’t understand how cruel they’re being, explaining this to them doesn’t make them stop nearly as well as just giving them a taste of what it’s like.